508 Sentences With "sidereal" | Random Sentence Generator

Their referent doesn't matter because I believe in Gechtoff's sidereal vision.

Note: For simplicity's sake, these are all sidereal days, and "day" refers to an Earth day.

Sidereal astrologers, on the other hand, still base their readings on the constellations and their current positions.

One tweet, in particular, has birthed a fair number of inky astronauts floating across a sidereal arm.

Sidereal and tropical astrology mainly differ in how their respective horoscopes are created — hence the added Ophiuchus sign.

Modern astronomers focus on the sidereal year, the time it takes Mars to orbit the sun — about 687 days .

The key difference here is that, whereas sidereal astrology sometimes includes Ophiuchus between Scorpio and Sagittarius, Western astrology always omits it.

Sidereal astrologers use the positions of fixed star systems and constellations, while tropical astrologers look to the sun's position in relation to the earth.

So, sidereal predictions tend to name when and how specific events will occur — it's for this reason that many consider them more precise and reliable.

This sidereal imagery made Mark uneasy—stars were almost always cheesy; doubly cheesy, in the context of a "pop star"—but he had nothing else.

His best piece in the gallery is "Sidereal Procession, the Adept In Public" (2017), a 12-foot-long frieze of 10 vessels set in vivid chroma.

After all, you only need to observe this 13th sign if you follow sidereal astrology (rather than what we practice here in the western world, tropical astrology).

With the recent landing of a sophisticated robot on Mars, we also note that mankind is interested in finding out the details of those sidereal, extra-terrestrial objects floating out there beyond the atmosphere of our Earth.

A solar day measures how long it takes for the Sun to return to the same point in the sky, while a sidereal day is the time it takes for a body to fully rotate on its axis.

It shows civil, solar and sidereal time or, respectively, standard time, time based on the trajectory of the sun (which can vary by as much as 14 additional to 16 fewer minutes a day), and time measured against the position of the stars.

The sidereal year is the length of time it takes for the Earth to return to the same place with respect to the "fix'd" and "constant" stars, so that Orion appears exactly in the same place in the sky, at exactly midnight, 365.2563 days later.

The "sidereal year" is the length of time it takes for the Earth to return to the same place with respect to the "fix'd" and "constant" stars, so that Orion appears exactly in the same place in the sky, at exactly midnight, 365.2563 days later.

Anti-sidereal time and extended-sidereal time are artificial time standards used to analyze the daily variation in the number of cosmic rays received on Earth. Anti-sidereal time has about 364.25 days per year, one day less than the number of days in a year of solar time, 365.25. Thus each anti-sidereal day is longer than a solar day (24 hr) by about four minutes or 24 hr 4 min. Extended-sidereal time has about 367.25 days per year, one day more than the number of days in a year of sidereal time, 366.25.

Similarly, an annual amplitude modulation of of the sidereal frequency, about , produces sidebands of and . The upper sideband of the solar frequency contaminates the amplitude of the sidereal frequency, while the lower sideband of the sidereal frequency contaminates the amplitude of the solar frequency. Because the magnitudes of the two sidebands produced by amplitude modulation of the solar frequency are the same and no known natural phenomenon recurs at , the spurious amplitude at the sidereal frequency can be corrected by subtracting any signal present at the anti- sidereal frequency. Similarly, the spurious amplitude in the solar frequency of per year can be corrected by subtracting any signal present at the extended-sidereal frequency of per year.

The sidereal day is based on the Earth's rotation rate relative to fixed stars, rather than the Sun. A sidereal day is approximately 23 hours, 56 minutes, 4.0905 SI seconds.

Unlike solar time, which is relative to the apparent position of the Sun, sidereal time is the measurement of time relative to that of a distant star. In astronomy, sidereal time is used to predict when a star will reach its highest point in the sky. Due to Earth's orbital motion around the Sun, a mean solar day is about 3 minutes 56 seconds longer than a mean sidereal day, or more than a mean sidereal day.

When it is then set to an observer's Local Mean Sidereal Time then a star will transit the meridian (passing directly north or south) at the sidereal time of the star's Right Ascension.

Photo of the face of the other surviving Sidereal Angle clock in the Royal Observatory in Greenwich, England, made by Thomas Tompion. The dial has been ornately inscribed with the name J Flamsteed, who was the Astronomer Royal, and the date 1691. Although ERA is intended to replace sidereal time, there is a need to maintain definitions for sidereal time during the transition, and when working with older data and documents. Similarly to mean solar time, every location on Earth has its own local sidereal time (LST), depending on the longitude of the point.

Mercury's sidereal day is about two- thirds of its orbital period, so by the prograde formula its solar day lasts for two revolutions around the Sun – three times as long as its sidereal day. Venus rotates retrograde with a sidereal day lasting about 243.0 Earth days, or about 1.08 times its orbital period of 224.7 Earth days; hence by the retrograde formula its solar day is about 116.8 Earth days, and it has about 1.9 solar days per orbital period. By convention, rotation periods of planets are given in sidereal terms unless otherwise specified.

Therefore, there is one fewer solar day per year than there are sidereal days. This makes a sidereal day approximately times the length of the 24-hour solar day, giving approximately 23 h 56 min 4.1 s (86,164.1 s).

According to the sidereal solar calendar, celebrations which originally coincided with the March equinox now take place throughout South Asia and parts of Southeast Asia on the day when the Sun enters the sidereal Aries, generally around 14 April.

Michael E. Bakich, The Cambridge planetary handbook, p.50. This is obtained by dividing Earth's equatorial circumference by . However, the use of the solar day is incorrect; it must be the sidereal day, so the corresponding time unit must be a sidereal hour. This is confirmed by multiplying by the number of sidereal days in one mean solar day, , which yields the equatorial speed in mean solar hours given above of .

As with orbital periods, a rotational period can be sidereal or synodic to describe a full rotation with respect to the fixed stars (sidereal) and Sun (synodic), respectively. In most cases, the periods given in this list are synodic, not sidereal. However, in most cases the difference between these two different measures is not significant. This is the case for all main-belt asteroids, which account for 97.5% of all minor planets.

If the position of the Earth (see above) is reckoned with respect to the fixed stars, then the dates indicate the zodiacal constellation near which the Sun can be found. A calendar of this type is called a sidereal solar calendar . The mean calendar year of such a calendar approximates the sidereal year. Indian calendars like the Hindu calendar, Tamil calendar, Bengali calendar (non-revised) and Malayalam calendar are sidereal solar calendars.

The Sun, Moon, and Venus Among the Stars: Methods for Mapping Mayan Sidereal Space. Archaeoastronomy, 17.

Using sidereal time, it is possible to easily point a telescope to the proper coordinates in the night sky. Briefly, sidereal time is a "time scale that is based on Earth's rate of rotation measured relative to the fixed stars". A more precise definition is given later in the lead. Viewed from the same location, a star seen at one position in the sky will be seen at the same position on another night at the same sidereal time.

Earth's rotation period relative to the International Celestial Reference Frame, called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is seconds of mean solar time (UT1) , ). Earth's rotation period relative to the precessing mean vernal equinox, named sidereal day, is of mean solar time (UT1) , ). Thus, the sidereal day is shorter than the stellar day by about . Both the stellar day and the sidereal day are shorter than the mean solar day by about .

Thus each extended-sidereal day is shorter than a sidereal day (23 hr 56 min) by about four minutes or 23 hr 52 min. All years mentioned have the same length.B. E. Kolterman, "A harmonic analysis of the large scale cosmic ray anisotropy", 30th International Cosmic Ray Conference (2007).

The Vikram Samvat uses lunar months and solar sidereal years. Because 12 months do not match a sidereal year, correctional months (adhika māsa) are added or (occasionally) subtracted (kshaya masa). A lunar year consists of 12 months, and each month has two fortnights. The lunar days are called tithis.

The time for one complete rotation is 23 hours, 56 minutes, and 4.09 seconds – one sidereal day. The first experimental demonstration of this motion was conducted by Léon Foucault. Because Earth orbits the Sun once a year, the sidereal time at any given place and time will gain about four minutes against local civil time, every 24 hours, until, after a year has passed, one additional sidereal "day" has elapsed compared to the number of solar days that have gone by.

Agathiyar Nādi Astrology (') is a form of Dharma astrology practiced in Tamil Nadu, Kerala, and adjacent regions in India. It is based on the belief that the past, present, and future lives of all humans were foreseen by Dharma sages in ancient time. Nadi astrology uses a sidereal zodiac system. Sidereal zodiac systems coincided with tropical zodiac systems around 2,000 years ago, but have now drifted apart due to sidereal systems accounting for the precession of the equinoxes while tropical systems do not.

Since it is not feasible to publish tables for every longitude, astronomical tables make use of Greenwich sidereal time (GST), which is sidereal time on the IERS Reference Meridian, less precisely called the Greenwich, or Prime meridian. There are two varieties, mean sidereal time if the mean equator and equinox of date are used, or apparent sidereal time if the apparent equator and equinox of date are used. The former ignores the effect of astronomical nutation while the latter includes it. When the choice of location is combined with the choice of including astronomical nutation or not, the acronyms GMST, LMST, GAST, and LAST result. The following relationships hold: The new definitions of Greenwich mean and apparent sidereal time (since 2003, see above) are: where θ is the Earth Rotation Angle, EPREC is the accumulated precession, and E0 is equation of the origins, which represents accumulated precession and nutation.

Sidereal time vs solar time. Above left: a distant star (the small orange star) and the Sun are at culmination, on the local meridian m. Centre: only the distant star is at culmination (a mean sidereal day). Right: a few minutes later the Sun is on the local meridian again.

However, it should not be confused with the sidereal zodiac, which is the background of fixed stars, or constellations.

After completing a sidereal month, the Moon must move a little further to reach the new position having the same angular distance from the Sun, appearing to move with respect to the stars since the previous month. Therefore, the synodic month takes 2.2 days longer than the sidereal month. Thus, about 13.37 sidereal months, but about 12.37 synodic months, occur in a Gregorian year. Since Earth's orbit around the Sun is elliptical and not circular, the speed of Earth's progression around the Sun varies during the year.

Walter Berg (born 1947) is a British astrologer, known for his system of a 13-sign sidereal astrology (13), "a sidereal system that uses the actual star constellations of the true zodiac". He has published several best selling books on horoscopy and divination in Japan and has appeared regularly on Fuji Television.

It gave a concurring sidereal period of hours and a spin axis at (355.0°, −78.0°) in ecliptic coordinates (λ, β).

Similarly, to ensure the ground track repeats every 24 hours the nodal period needed to be half a sidereal day.

Alternatively, the equation of the origins is the difference between the Earth Rotation Angle and the apparent sidereal time at Greenwich.

It gave a sidereal period of and two spin axes at (94.0°, −25.0°) and (269.0°, 4.0°) in ecliptic coordinates (λ, β).

It gave a concurring sidereal period of hours and includes a partial spin axis at (β1 −53.0°) in ecliptic coordinates (λ, β).

Common time on a typical clock measures a slightly longer cycle, accounting not only for Earth's axial rotation but also for Earth's orbit around the Sun. A sidereal day is approximately 23 hours, 56 minutes, 4.0905 seconds (24 hours − 4 minutes + 4.0905 seconds = 86164.0905 s = 23.9344696 h). (Seconds here follow the SI definition and are not to be confused with ephemeris second.) The March equinox itself precesses slowly westward relative to the fixed stars, completing one revolution in about 26,000 years, so the misnamed sidereal day ("sidereal" is derived from the Latin sidus meaning "star") is 0.0084 seconds shorter than the stellar day, Earth's period of rotation relative to the fixed stars. The slightly longer "true" sidereal period is measured as the Earth Rotation Angle (ERA), formerly the stellar angle.

Parallel transport of a vector around a closed loop on the sphere: The angle by which it twists, , is proportional to the area inside the loop. In a near- inertial frame moving in tandem with Earth, but not sharing the rotation of the earth about its own axis, the suspension point of the pendulum traces out a circular path during one sidereal day. At the latitude of Paris, 48 degrees 51 minutes north, a full precession cycle takes just under 32 hours, so after one sidereal day, when the Earth is back in the same orientation as one sidereal day before, the oscillation plane has turned by just over 270 degrees. If the plane of swing was north–south at the outset, it is east–west one sidereal day later.

It showed a sidereal period of hours (), and gave two spin axes at (18.0°, 4.0°) and (192.0°, 32.0°) in ecliptic coordinates (λ, β).

Rachael Boast (born 1975) is a British poet. She has published three poetry collections: Sidereal (2011), Pilgrim Flowers (2013) and Void Studies (2016).

Sidereal time is the hour angle of the equinox. However, there are two types: if the mean equinox is used (that which only includes precession), it is called mean sidereal time; if the true equinox is used (the actual location of the equinox at a given instant), it is called apparent sidereal time. The difference between these two is known as the equation of the equinoxes, and is tabulated in Astronomical Almanacs. A related concept is known as the equation of the origins, which is the arc length between the Celestial Intermediate Origin and the equinox.

So after a sidereal day has passed, Earth still needs to rotate slightly more before the Sun reaches local noon according to solar time. A mean solar day is, therefore, nearly 4 minutes longer than a sidereal day. The stars are so far away that Earth's movement along its orbit makes nearly no difference to their apparent direction (see, however, parallax), and so they return to their highest point in a sidereal day. Another way to see this difference is to notice that, relative to the stars, the Sun appears to move around Earth once per year.

Modelling gave a concurring sidereal rotation period of hours, as well as two spin axes of (132.0°, −46.0°) and (305.0°, −49.0°) in ecliptic coordinates.

It gave a concurring sidereal period of hours and includes two spin axes at (119.0°, 7.0°) and (301.0°, 5.0°) in ecliptic coordinates (λ, β).

It gave a sidereal period of 20.9959 hours, as well as a spin axis in ecliptic coordinates (λ, β) of (326.0°, 37.0°) and (144.0°, 79.0°).

The Hindu cosmological time cycles explained in the Surya Siddhanta, give the average length of the sidereal year (the length of the Earth's revolution around the Sun) as 365.2563627 days, which is only 1.4 seconds longer than the modern value of 365.256363004 days. This remains the most accurate estimate for the length of the sidereal year anywhere in the world for over a thousand years.

An increase of 360° in the ERA is a full rotation of the Earth. Because Earth orbits the Sun once a year, the sidereal time at any given place and time will gain about four minutes against local civil time, every 24 hours, until, after a year has passed, one additional sidereal "day" has elapsed compared to the number of solar days that have gone by.

The nodal period (or draconic period) of a satellite is the time interval between successive passages of the satellite through either of its orbital nodes, typically the ascending node. This type of orbital period applies to artificial satellites, like those that monitor weather on Earth, and natural satellites like the Moon. It is distinct from the sidereal period, which measures the period with respect to reference stars seemingly fixed onto a spherical background, since the location of a satellite's nodes precess over time. For example, the nodal period of the Moon is 27.2122 days (one draconic month), while its sidereal period is 27.3217 days (one sidereal month).

This yielded a sidereal rotation period of . They found two possible solutions for the spin axis, with the preferred solution in ecliptic coordinates being (λ, β) = (, ).

It gave a concurring sidereal period of 7.87149 hours, as well as two spin axes of (7.0°, 55.0°) and (170.0°, 65.0°) in ecliptic coordinates (λ, β).

The sidereal year is 20 min 24.5 s longer than the mean tropical year at J2000.0 . Before the discovery of the precession of the equinoxes by Hipparchus in the Hellenistic period, the difference between sidereal and tropical year was unknown. For naked-eye observation, the shift of the constellations relative to the equinoxes only becomes apparent over centuries or "ages", and pre-modern calendars such as Hesiod's Works and Days would give the times of the year for sowing, harvest, and so on by reference to the first visibility of stars, effectively using the sidereal year. The South and Southeast Asian solar New Year, based on Indic influences, is traditionally reckoned by the Sun's entry into Aries and thus the sidereal year, but is also supposed to align with the spring equinox and have relevance to the harvesting and planting season and thus the tropical year.

Most recent results gave a concurring sidereal period of hours, as well as two spin axes at (325.0°, 35.0°) and (137.0°, 66.0°) in ecliptic coordinates (λ, β).

It gave a concurring sidereal period of and hours, respectively. Hanuš also gave two spin axes at (235.0°, −52.0°) and (47.0°, 84.0°) in ecliptic coordinates (λ, β).

For example, if a star with RA = is at its meridian, then a star with RA = will be on the/at its meridian (at its apparent highest point) 18.5 sidereal hours later. Sidereal hour angle, used in celestial navigation, is similar to right ascension, but increases westward rather than eastward. Usually measured in degrees (°), it is the complement of right ascension with respect to 24h.Explanatory Supplement (1992), p. 11.

The period of one sidereal day ensures that the satellites follows the same ground track over time. This is controlled by the semi-major axis of the orbit.

It is important not to confuse sidereal hour angle with the astronomical concept of hour angle, which measures angular distance of an object westward from the local meridian.

This is similar to how the time kept by a sundial can be used to find the location of the Sun. Just as the Sun and Moon appear to rise in the east and set in the west due to the rotation of Earth, so do the stars. Both solar time and sidereal time make use of the regularity of Earth's rotation about its polar axis, solar time following the Sun while sidereal time roughly follows the stars. More exactly, sidereal time is the angle, measured along the celestial equator, from the observer's meridian to the great circle that passes through the March equinox and both celestial poles, and is usually expressed in hours, minutes, and seconds.

Elements by Simon Newcomb The low eccentricity and comparatively small size of its orbit give Venus the least range in distance between perihelion and aphelion of the planets: 1.46 Gm. The planet orbits the Sun once every 225 daysThe sidereal and anomalistic years are both 224.7008 days long. The sidereal year is the time taken to revolve around the Sun relative to a fixed reference frame. More precisely, the sidereal year is one way to express the rate of change of the mean longitude at one instant, with respect to a fixed equinox. The calculation shows how long it would take for the longitude to make one revolution at the given rate.

At the equator, the solar rotation period is 24.47 days. This is called the sidereal rotation period, and should not be confused with the synodic rotation period of 26.24 days, which is the time for a fixed feature on the Sun to rotate to the same apparent position as viewed from Earth. The synodic period is longer because the Sun must rotate for a sidereal period plus an extra amount due to the orbital motion of Earth around the Sun. Note that astrophysical literature does not typically use the equatorial rotation period, but instead often uses the definition of a Carrington rotation: a synodic rotation period of 27.2753 days or a sidereal period of 25.38 days.

Astrology has used the concept of classical elements from antiquity up until the present. In Western astrology and Sidereal astrology four elements are used: Fire, Earth, Air, and Water.

The observatory published The Sidereal Messenger from 1882 to 1892, later renamed Astronomy and Astro-Physics from 1893 to ~1896. In 1893, a successor publication, Popular Astronomy, was established.

In 2013, an international study modeled a lightcurve with a sidereal period of 8.82653 hours and found two spin axes at (47.0°, 57.0°) and (234.0°, 50.0°) in ecliptic coordinates (λ, β) ().

The Western Zodiac is drawn based on the Earth's relationship to fixed, designated positions in the sky, and the Earth's seasons. The Sidereal Zodiac is drawn based on the Earth's position in relation to the constellations, and follows their movements in the sky. Due to a phenomenon called precession of the equinoxes (where the Earth's axis slowly rotates like a spinning top in a 25,700-year cycle), there is a slow shift in the correspondence between Earth's seasons (and calendar) and the constellations of the zodiac. Thus, the tropical zodiac corresponds with the position of the earth in relation to fixed positions in the sky (Western Astrology), while the sidereal zodiac is drawn based on the position in relation to the constellations (sidereal zodiac).

The periods are derived from polynomial expressions for Delaunay's arguments used in lunar theory, as listed in Table 4 of Chapront, Chapront-Touzé & Francou (2002): W1 is the ecliptic longitude of the Moon w.r.t. the fixed ICRS equinox: its period is the sidereal month. If we add the rate of precession to the sidereal angular velocity, we get the angular velocity w.r.t. the equinox of the date: its period is the tropical month, which is rarely used.

In 1989, Patek Philippe created Calibre 89, then the most complicated mechanical watch ever made, for its 150th anniversary. Calibre 89 holds 33 complications, including the date of Easter, time of sunrise, equation of time, sidereal time, and many other indicators. 1,728 unique parts allow sidereal time, a 2,800 star chart, and more. In addition, Calibre 89 is able to add a day to February for leap years while leaving out the extra day for every 100 year interval.

In 2016, a modeled lightcurve using photometric data from various sources, rendered a similar sidereal period of 12.15186 hours and two spin axes of (32.0°, 22.0°) and (216.0°, 55.0°) in ecliptic coordinates.

As these have grown apart, in some countries and cultures the date has been fixed according to the tropical year while in others the astronomical calculation and sidereal year is still used.

A heliacal year is the interval between the heliacal risings of a star. It differs from the sidereal year for stars away from the ecliptic due mainly to the precession of the equinoxes.

Richard Christopher Carrington determined the solar rotation rate from low latitude sunspots in the 1850s and arrived at 25.38 days for the sidereal rotation period. Sidereal rotation is measured relative to the stars, but because the Earth is orbiting the Sun, we see this period as 27.2753 days. It is possible to construct a diagram with the longitude of sunspots horizontally and time vertically. The longitude is measured by the time of crossing the central meridian and based on the Carrington rotations.

Approximately every 26,000 years the zodiacal constellations, the associated sidereal zodiac, and the tropical zodiac used by western astrologers basically align. Technically this is when the tropical and sidereal "first point in Aries" (Aries 0°) coincided. This alignment is often called the fiducial point and, if the fiducial point could be found, fairly exact timeframes of all the astrological ages could be accurately determined if the method used to determine the astrological ages is based on the equal- sized 30 degrees per age and do not correspond to the exact constellation configuration in the sky. However this fiducial point is difficult to determine because while there is no ambiguity about the tropical zodiac used by western astrologers, the same cannot be said of the sidereal zodiac used by Vedic astrologers.

The Sothic year is the interval between heliacal risings of the star Sirius. It is currently less than the sidereal year and its duration is very close to the Julian year of 365.25 days.

John Arnold & Son. It was previously owned by Sir George Shuckburgh-Evelyn. It is on display in the Royal Observatory, Greenwich, London. Sidereal time is a timekeeping system that astronomers use to locate celestial objects.

The seasonal and sidereal calendar, on the other hand, was immune to interference so Thucydides could date by the rising of Arcturus without having to wade into the confusion of disconnected city-state calendars.Thucydides, 2.78.2.

Such an arrangement is called a sidereal or clock drive. The green equatorially mounted telescope rotates at the same rate as the earth but in the opposite direction, while the red telescope is not driven.

Photometric measurements during 2009 produced a lightcurve that indicated a sidereal rotation period of with a variation amplitude of magnitudes. This result conflicted with previous determinations of the period, so the latter were ruled out.

As seen from above the Earth's north pole, a star's local hour angle (LHA) for an observer near New York. Also depicted are the star's right ascension and Greenwich hour angle (GHA), the local mean sidereal time (LMST) and Greenwich mean sidereal time (GMST). The symbol ʏ identifies the vernal equinox direction. The right ascension symbol , (lower case "alpha", abbreviated RA) measures the angular distance of an object eastward along the celestial equator from the vernal equinox to the hour circle passing through the object.

As seen from above the Earth's north pole, a star's local hour angle (LHA) for an observer near New York (red dot). Also depicted are the star's right ascension and Greenwich hour angle (GHA), the local mean sidereal time (LMST) and Greenwich mean sidereal time (GMST). The symbol ʏ identifies the vernal equinox direction. Assuming in this example the day of the year is the March equinox so the sun lies in the direction of the grey arrow then this star will rise about midnight.

A Gaussian year is defined as 365.2568983 days. It was adopted by Carl Friedrich Gauss as the length of the sidereal year in his studies of the dynamics of the solar system. A slightly different value is now accepted as the length of the sidereal year, and the value accepted by Gauss is given a special name. A particle of negligible mass, that orbits a body of 1 solar mass in this period, has a mean axis for its orbit of 1 astronomical unit by definition.

Two modeled lightcurves, published by Josef Ďurech and Josef Hanuš in 2016, using photometric data from the Lowell Photometric Database (LPD) and other sources, gave a sidereal period of and , respectively. Each modeled lightcurve also determined two spin axes of (99.0°, 67.0°) and (283.0°, 30.0°), as well as (282.0°, 35.0°) and (103.0°, 68.0°) in ecliptic coordinates (λ, β), respectively. The online version of the Database of Asteroid Models from Inversion Techniques gives two poles at (103°, 68.0°) and (282°, 35.0°) with a nearly identical sidereal period.

A modeled lightcurve using photometric data from the Lowell Photometric Database was published in 2016. It gave a sidereal period of 42.8982 hours, as well as a spin axis at (352.0°, −66.0°) in ecliptic coordinates (λ, β).

Productions here included: The Kingdom, The Suicide, Poems for the Theater, The Device Machine, Lendra // Revolute, John Day, Galileo Sidereal, Witkacy's The Madman and the Nun, Heiner Müller's Mommsen's Block, The Battle (Die Schlacht), Prolegomenon, and Pickaxe.

Information on Earnshaw's first clock at the Armagh Observatory website. The Observatory also purchased Earnshaw's second clockInformation on Earnshaw's second clock at the Armagh Observatory website. which was operated at sidereal rate with Edward Troughton's Equatorial Telescope.

They gave a concurring sidereal period of 11.3981 and 11.39823 hours, respectively. Each study also determined two respective spin axes of (79.0°, 75.0°) and (282.0°, 55.0°), and (71.0°, 61.0°) and (280.0°, 54.0°) in ecliptic coordinates (λ, β).

A subsynchronous orbit is an orbit of a satellite that is nearer the planet than it would be if it were in synchronous orbit, i.e. the orbital period is less than the sidereal day of the planet.

Used for mean new moons, both in Hebrew calendar cycles and in equivalent astronomical cycles. With this definition, the second was proposed in 1874 as the base unit of time in the CGS system of units. Soon afterwards Simon Newcomb and others discovered that Earth's rotation period varied irregularly, so in 1952, the International Astronomical Union (IAU) defined the second as a fraction of the sidereal year. In 1955, considering the tropical year to be more fundamental than the sidereal year, the IAU redefined the second as the fraction of the 1900.0 mean tropical year.

The SI second was made equal to the ephemeris second in 1967. Earth's rotation period relative to the fixed stars, called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is seconds of mean solar time (UT1) Earth's rotation period relative to the precessing or moving mean vernal equinox, its sidereal day, is seconds of mean solar time (UT1) Thus the sidereal day is shorter than the stellar day by about 8.4 ms.Explanatory Supplement to the Astronomical Almanac, ed. P. Kenneth Seidelmann, Mill Valley, Cal.

The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars. For objects in the Solar System, this is often referred to as the sidereal period, determined by a 360° revolution of one celestial body around another, e.g. the Earth orbiting the Sun. The term sidereal denotes that the object returns to the same position relative to the fixed stars projected in the sky.

Two kinds of year are relevant to understanding his work. The tropical year is the length of time that the Sun, as viewed from the Earth, takes to return to the same position along the ecliptic (its path among the stars on the celestial sphere). The sidereal year is the length of time that the Sun takes to return to the same position with respect to the stars of the celestial sphere. Precession causes the stars to change their longitude slightly each year, so the sidereal year is longer than the tropical year.

Using observations of the equinoxes and solstices, Hipparchus found that the length of the tropical year was 365+1/4−1/300 days, or 365.24667 days (Evans 1998, p. 209). Comparing this with the length of the sidereal year, he calculated that the rate of precession was not less than 1° in a century. From this information, it is possible to calculate that his value for the sidereal year was 365+1/4+1/144 days (Toomer 1978, p. 218). By giving a minimum rate he may have been allowing for errors in observation.

Sankranti ( saṁkrānti) means transmigration of the Sun from one Rāshi (constellation of the zodiac in Indian astronomy) to the next. Hence, there are 12 Sankrantis in a year. Each Sankranti is marked as the beginning of a month in the sidereal solar calendars followed in Andhra Pradesh, Telangana, Karnataka, Kerala, Maharashtra, Gujarat, Punjab, Odisha and Nepal. On the other hand, in the sidereal solar Bengali calendar and Assamese calendar, a Sankranti is marked as the end of each month and the day following as the beginning of a new month.

A sidereal year (, ; from Latin "asterism, star") is the time taken by the Earth to orbit the Sun once with respect to the fixed stars. Hence, it is also the time taken for the Sun to return to the same position with respect to the fixed stars after apparently travelling once around the ecliptic. It equals for the J2000.0 epoch. The sidereal year differs from the tropical year, "the period of time required for the ecliptic longitude of the Sun to increase 360 degrees", due to the precession of the equinoxes.

Contemporary use of the coordinate system is presented with the choice of interpreting the system either as sidereal, with the signs fixed to the stellar background, or as tropical, with the signs fixed to the point (vector of the Sun) at the March equinox.Rochberg, Francesca (1998), "Babylonian Horoscopes", American Philosophical Society, New Series, Vol. 88, No. 1, pp i-164 Western astrology takes the tropical approach, whereas Hindu astrology takes the sidereal one. This results in the originally unified zodiacal coordinate system drifting apart gradually, with a clockwise (westward) precession of 1.4 degrees per century.

In 2016, a modeled lightcurve using photometric data from various sources of an international collaboration of astronomers, rendered a concurring sidereal period of and two spin axes of (40.0°, 5.0°) and (225.0°, 16.0°) in ecliptic coordinates (λ, β).

They gave a concurring sidereal period of 7.88695 and 7.88697 hours. Each of the studies also determined two spin axis in ecliptic coordinates (λ, β): (142.0°, −50.0°) and (305.0°, −45.0°), as well as (130.0°, −44.0°) and (312.0°, −51.0°).

He made a sidereal clock for the City Observatory, formerly the Calton Hill Observatory,Astronomical Society of Edinburgh. "Instruments of the City Observatory". Retrieved 27-01-2020. where it was used by Professor Thomas Henderson in his observations.

On 27 October 2010 the Bailey-Salgado Project previewed Sidereal Motion at the 7th international conference on the Inspiration of Astronomical Phenomena (INSAP) at the Bath Royal Literary & Scientific Institution in Bath, England with Bailey improvising on keyboard.

Hirsch was featured in the eighth episode of season 2 of the HBO Television series Boardwalk Empire, where he was played by Robert Dorfman. There he was seen to be employed by Arnold Rothstein for training his racehorse Sidereal.

He reckoned the value as 1° per century, a value that was not improved upon until about 1000 years later, by Islamic astronomers. Since this discovery a distinction has been made between the tropical year and the sidereal year .

This led to the determination of UT1 (mean solar time at 0° longitude) using VLBI, a new measure of the Earth Rotation Angle, and new definitions of sidereal time. These changes were put into practice on 1 January 2003.

In 2013, the asteroid's lightcurve was also modeled from combined dense and sparse photometry. It gave a concurring sidereal period of 4.714793 hours. The modelling also determined two spin axis of (345.0°, −22.0°) and (173.0°, −3.0°) in ecliptic coordinates (λ, β).

The orbital period is one-half a sidereal day, i.e., 11 hours and 58 minutes so that the satellites pass over the same locationsWhat the Global Positioning System Tells Us about Relativity . Retrieved January 2, 2007. or almost the same locations.

In 2011, a modeled lightcurve using data from the Uppsala Asteroid Photometric Catalogue and other sources gave a concurring sidereal period of 3.081545 hours, as well as two spin axis of (268.0°, 23.0°) and (87.0°, 28.0°) in ecliptic coordinates (λ, β).

In 2016, a rotational lightcurve of Riceia was modeled from photometric data from the Lowell Photometric Database. Lightcurve analysis gave a sidereal rotation period of 6.67317 hours as well as a spin axis of (37.0°, −63.0°) in ecliptic coordinates (λ, β).

In 2016, the asteroid's lightcurve has been modeled using data from Lowell photometric database, which gave a sidereal rotation period of 7.43019 hours, as well as two spin axes of (72.0°, −64.0°) and (288.0°, −55.0°) in ecliptic coordinates (λ, β) ().

Venus rotates once every 243 Earth days—by far the slowest rotation period of any known object in the Solar System. A Venusian sidereal day thus lasts more than a Venusian year (243 versus 224.7 Earth days). However, the length of a solar day on Venus is significantly shorter than the sidereal day; to an observer on the surface of Venus, the time from one sunrise to the next would be 116.75 days. Therefore, the slow Venerian rotation rate would result in extremely long days and nights, similar to the day-night cycles in the polar regions of earth — shorter, but global.

In the 2nd half of the nineteenth century, the firm provided sidereal regulators for new observatories being established worldwide, notably in Australia at Sydney and Melbourne; in Italy at Padua, Palermo and Naples; and in the USA at Harvard and Lick. Kew Observatory. Sidereal regulator now on display at the Norman Lockyer Observatory, originally installed at the Solar Physics Observatory in South Kensington. In addition to the production of standard high-grade pocket watches and domestic clocks, the firm specialised in complicated timepieces, including Tourbillon and Karrusel watches, many of which were submitted for observatory testing, frequently scoring highly.

As a result, the time it takes the Moon to return to the same node is shorter than a sidereal month, lasting days (27 d 5 h 5 m 35.8 s). The line of nodes of the Moon's orbit precesses 360° in about 6,798 days (18.6 years). A draconic month is shorter than a sidereal month because the nodes precess in the opposite direction to that in which the Moon is orbiting Earth, one rotation every 18.6 years. Therefore, the Moon returns to the same node slightly earlier than it returns to meet the same reference star.

The Coriolis force at latitude is horizontal in the small angle approximation and is given by where is the rotational frequency of Earth, is the component of the Coriolis force in the -direction and is the component of the Coriolis force in the -direction. The restoring force, in the small-angle approximation, is given by Graphs of precession period and precession per sidereal day vs latitude. The sign changes as a Foucault pendulum rotates anticlockwise in the Southern Hemisphere and clockwise in the Northern Hemisphere. The example shows that one in Paris precesses 271° each sidereal day, taking 31.8 hours per rotation.

Its duration is about 27.21222 days on average. A synodic month is longer than a sidereal month because the Earth-Moon system is orbiting the Sun in the same direction as the Moon is orbiting the Earth. The Sun moves eastward with respect to the stars (as does the Moon) and it takes about 2.2 days longer for the Moon to return to the same apparent position with respect to the Sun. An anomalistic month is longer than a sidereal month because the perigee moves in the same direction as the Moon is orbiting the Earth, one revolution in nine years.

According to mathematician-historian Montucla, the Hindu zodiac was adopted from the Greek zodiac through communications between ancient India and the Greek empire of Bactria. The Hindu zodiac uses the sidereal coordinate system, which makes reference to the fixed stars. The tropical zodiac (of Mesopotamian origin) is divided by the intersections of the ecliptic and equator, which shifts in relation to the backdrop of fixed stars at a rate of 1° every 72 years, creating the phenomenon known as precession of the equinoxes. The Hindu zodiac, being sidereal, does not maintain this seasonal alignment, but there are still similarities between the two systems.

In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from a large collaboration of individual observers (such as above). The study also determined two spin axes of (42.0°, 44.0°) and (226.0°, 73.0°) in ecliptic coordinates (λ, β).

In 2018, Czech astronomers Josef Ďurech and Josef Hanuš published a modeled lightcurve using photometric data from the Gaia spacecraft's second data release. It showed a sidereal period of hours (), and gave a spin axis at (18.0°, 78.0°) in ecliptic coordinates (λ, β).

This is an S-type asteroid around 86 km with an elliptical ratio of 1.51. The sidereal rotation period is 13.6217 hours. Based on the lightcurve data obtained from Nausikaa, a possible satellite was reported in 1985. However, this has not been confirmed.

The Thai solar calendar, when based on the Hindu solar calendar was also a sidereal calendar. They are calculated on the basis of the apparent motion of the Sun through the twelve zodiacal signs rather than the tropical movement of the Earth.

Based on an individual's sidereal horoscope, either a single gem or a combination of compatible gems is advised to be worn to harness beneficial planets or counteract harmful planets. The supposed "astrological" or "piezoelectric" benefit of wearing or donating gems has not been scientifically quantified.

The Chinese, Coligny and HebrewThe modern Hebrew calendar, since it is based on rules rather than observations, does not exactly track the tropical year, and in fact the average Hebrew year of ~365.2468 days is intermediate between the tropical year (~365.2422 days) and the sidereal year (~365.2564 days). lunisolar calendars track more or less the tropical year whereas the Buddhist and Hindu lunisolar calendars track the sidereal year. Therefore, the first three give an idea of the seasons whereas the last two give an idea of the position among the constellations of the full moon. The Tibetan calendar was influenced by both the Chinese and Buddhist calendars.

Grofe believes that this interval is quite close to a whole multiple of the sidereal year, returning the sun to precisely the same position against the background of stars. He proposes that this is an observation of the precession of the equinoxes and that the serpent series shows how the Maya calculated this by observing the sidereal position of total lunar eclipses at fixed points within the tropical year.Grofe, Michael John 2007 The Serpent Series: Precession in the Maya Dresden Codex p. vii Bricker and Bricker think that he based this on misinterpretation of the epigraphy and give their reasons in Astronomy in the Maya Codices.

Vedic astrologers do not have unanimity on the exact location in space of their sidereal zodiac. This is because the sidereal zodiac is superimposed upon the irregular zodiacal constellation, and there are no unambiguous boundaries of the zodiacal constellations. Modern day astronomers have defined boundaries, but this is a recent development by astronomers who are divorced from astrology, and cannot be assumed to be correct from the astrological perspective. While most astronomers and some astrologers agree that the fiducial point occurred in or around the 3rd to 5th centuries AD, there is no consensus on any exact date or tight timeframe within these three centuries.

The following types of months are mainly of significance in astronomy, most of them (but not the distinction between sidereal and tropical months) first recognized in Babylonian lunar astronomy. # The sidereal month is defined as the Moon's orbital period in a non-rotating frame of reference (which on average is equal to its rotation period in the same frame). It is about 27.32166 days (27 days, 7 hours, 43 minutes, 11.6 seconds). It is closely equal to the time it takes the Moon to pass twice a "fixed" star (different stars give different results because all have a very small proper motion and are not really fixed in position).

The celestial sphere is an imaginary globe of infinite size with the Earth at its center.Bowditch, 2002, p. 234. Positions on the celestial sphere are often expressed using two coordinates: declination and sidereal hour angle, which are similar to latitude and longitude on the surface of the Earth. To define declination, the Earth's equator is projected out to the celestial sphere to construct the celestial equator, and declination is measured in degrees north or south of this celestial equator. Sidereal hour angle is a measurement between 0° and 360°, indicating how far west a body is from an arbitrarily chosen point on the celestial sphere called the First Point of Aries.

In 2018, Czech astronomers Josef Ďurech and Josef Hanuš published a modeled lightcurve using photometric data from the Gaia probe's second data release. It showed a sidereal period of hours (), and gave two spin axes at (37.0°, 24.0°) and (220.0°, 7.0°) in ecliptic coordinates (λ, β).

Uttara KalamritaKalidasa, Uttara Kalamrita. Ranjan Publications(India, 1994) is a reference work on Vedic astrology or Jyotisa. It is also termed as sidereal astrology, written by Kalidasa. However, it is unknown whether the Kalidasa who wrote this work is the same Kalidasa who wrote Raghuvamsha and Abhijñānaśākuntalam.

For purposes of identification, the positions of navigational stars -- expressed as declination and sidereal hour angle -- are often rounded to the nearest degree. In addition to tables, star charts provide an aid to the navigator in identifying the navigational stars, showing constellations, relative positions, and brightness.

For a rigid Earth which is an oblate spheroid to a good approximation, the figure axis F would be its geometric axis defined by the geographic north and south pole, and identical with the axis of its polar moment of inertia. The Euler period of free nutation is (1) τE = 1/νE = A/(C − A) sidereal days ≈ 307 sidereal days ≈ 0.84 sidereal years νE = 1.19 is the normalized Euler frequency (in units of reciprocal years), C = 8.04 × 1037 kg m2 is the polar moment of inertia of the Earth, A is its mean equatorial moment of inertia, and C - A = 2.61 × 1035 kg m2. The observed angle between the figure axis of the Earth F and its angular momentum M is a few hundred milliarcseconds (mas). This rotation can be interpreted as a linear displacement of either geographical pole amounting to several meters on the surface of the Earth: 100 mas subtends an arc length of 3.082 m, when converted to radians and multiplied by the Earth's polar radius (6,356,752.3 m).

A modeled lightcurve using photometric data from the Lowell Photometric Database and from the Wide-field Infrared Survey Explorer (WISE) was published in 2018. It gave a divergent sidereal period of hours and includes two spin axes at (172.0°, 20.0°) and (352.0°, 42.0°) in ecliptic coordinates (λ, β).

The Moon's appearance is considerably more complex. Its motion, like the Sun, is between two limits—known as lunistices rather than solstices. However, its travel between lunistices is considerably faster. It takes a sidereal month to complete its cycle rather than the year-long trek of the Sun.

Nowadays, UT is the observed orientation of the Earth relative to an inertial reference frame formed by extra-galactic radio sources, modified by an adopted ratio between sidereal time and solar time. Its measurement by several observatories is coordinated by the International Earth Rotation and Reference Systems Service (IERS).

He worked as a watchmaker. In 1823 he won the National Exhibition Gold Medal for inventing a watch that showed sidereal and mean time. He invented the differential in 1827 (known in French as the différentiel mécanique). He invented it whilst at the Conservatoire des Arts et Métiers.

Pisces map showing Revati Revathi is the Hindu name for Zeta Piscium, a star on the edge of the Pisces zodiac constellation. In Hindu sidereal astronomy this star is identified as the First Point of Aries, i.e. when the Sun crosses this star, a new solar year begins.

Popular Astronomy is an American magazine published by John August Media, LLC and hosted at TechnicaCuriosa.com for amateur astronomers. Prior to its revival in 2009, the title was published between 1893 and 1951. It was the successor to The Sidereal Messenger, which was published from March 1882 to 1892.

According to Vasishtha Siddhantha (the treatise of Vasishtha), Purushottam Maas or the extra lunar month occurs after every 32 months, 16 days and 8 ghati. (A ghati is th of a sidereal day, approximately 24 minutes, so 8 ghati is about 3 hours.) In this reference the concept of Adhik Maas is unique to the traditional Hindu lunar calendars.12 important facts about Adhik Mass you must know! It is one of the most accurate methods to adjust the gap between Solar and Lunar Year. When the Sun does not at all transit into a new rāshi (30° sidereal zodiac) but simply keeps moving within a rāshi in a lunar month (i.e.

Firstly, in the unusual event of having an astronomer present, the sun's transit across the meridian (the moment the sun passed overhead) was noted, the clock was then set to noon and offset by the number of minutes given by the equation of time for that date. Secondly, and much more commonly, a sundial was read, a table of the equation of time (usually engraved on the dial) was consulted and the watch or clock set accordingly. These calculated the mean time, albeit local to a point of longitude. The third method did not use the equation of time; instead, it used stellar observations to give sidereal time, exploiting the relationship between sidereal time and mean solar time.

The Burmese calendar (, , or , ; Burmese Era (BE) or Myanmar Era (ME)) is a lunisolar calendar in which the months are based on lunar months and years are based on sidereal years. The calendar is largely based on an older version of the Hindu calendar, though unlike the Indian systems, it employs a version of the Metonic cycle. The calendar therefore has to reconcile the sidereal years of the Hindu calendar with the Metonic cycle's near tropical years by adding intercalary months and days at irregular intervals. The calendar has been used continuously in various Burmese states since its purported launch in 640 CE in the Sri Ksetra Kingdom, also called the Pyu era.

Animation (not to scale) showing geosynchronous satellite orbiting the Earth. A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbital period means that, for an observer on Earth's surface, an object in geosynchronous orbit returns to exactly the same position in the sky after a period of one sidereal day. Over the course of a day, the object's position in the sky may remain still or trace out a path, typically in a figure-8 form, whose precise characteristics depend on the orbit's inclination and eccentricity.

Based upon photometry observations between 1984−2007, it has a sidereal rotation period of 8.283065 h with an amplitude that can range up to in magnitude. The lightcurve shows some shape irregularities. There are two valid solutions for the pole's ecliptic coordinates: (λ1, β1) = (38°, +75°) and (λ2, β2) = (237°, +73°).

Recently (1999–2005) the average annual length of the mean solar day in excess of 86400 SI seconds has varied between 0.3 ms and 1 ms, which must be added to both the stellar and sidereal days given in mean solar time above to obtain their lengths in SI seconds.

360 Carlova is a very large main-belt asteroid. It is classified as a C-type asteroid and is probably composed of carbonaceous material. The asteroid has a convex, roughly ellipsoid shape. The sidereal rotation period is 6.1873 hours with an axis of rotation along the ecliptic coordinates (l, b) = (, ).

Various assertions have been made that other cultures discovered precession independently of Hipparchus. According to Al- Battani, the Chaldean astronomers had distinguished the tropical and sidereal year so that by approximately 330 BC, they would have been in a position to describe precession, if inaccurately, but such claims generally are regarded as unsupported.

There are several types of lunar month. The term lunar month usually refers to the synodic month because it is the cycle of the visible phases of the Moon. Most of the following types of lunar month, except the distinction between the sidereal and tropical months, were first recognized in Babylonian lunar astronomy.

In 2016, a lightcurve of Salonta has also been modeled using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and from individual observers. Modelling gave a concurring sidereal period of 8.86985 hours as well as two spin axis of (223.0°, 18.0°) and (57.0°, 35°) in ecliptic coordinates (λ, β).

In 2013, an international study modeled a lightcurve from various data sources including the Uppsala Asteroid Photometric Catalogue and the Palomar Transient Factory survey. The lightcurve gave a sidereal period of 29.4674 hours and allowed for the determination of two spin axis of (156.0°, −4.0°) and (338.0°, 15.0°) in ecliptic coordinates (λ, β).

Vikram Samvat (IAST: Vikrama Samvat; abbreviated V.S. (or VS) and B.S. (or BS); ) and also known as the Vikrami calendar, is the historical Hindu calendar in the Indian subcontinent. It is the official calendar of Nepal. In India it is used in several states. The calendar uses lunar months and solar sidereal years.

The Bullhead variation of the calibre 930 movement was also produced branded by Bucherer and Lemania as well a Richard chronograph. There was also a non date variation produced by Lemania without the internal rotating bezel as well as a composite cased model produced by Tissot as part of their Sidereal range.

The planet Venus rotates once every 224.7 days – by far the slowest rotation period of any of the major planets. In contrast, the gas giant Jupiter's sidereal day is only 9 hours and 56 minutes. However, it is not just the sidereal rotation period which determines the length of a planet's day-night cycle but the length of its orbital period as well - Venus has a rotation period of 224.7 days, but a day-night cycle just 116.75 days long due to its retrograde rotation and orbital motion around the Sun. Mercury has the longest day-night cycle as a result of its 3:2 resonance between its orbital period and rotation period - this resonance gives it a day-night cycle that is 176 days long.

In the past, time was measured by observing stars with instruments such as photographic zenith tubes and Danjon astrolabes, and the passage of stars across defined lines would be timed with the observatory clock. Then, using the right ascension of the stars from a star catalog, the time when the star should have passed through the meridian of the observatory was computed, and a correction to the time kept by the observatory clock was computed. Sidereal time was defined such that the March equinox would transit the meridian of the observatory at 0 hours local sidereal time. Beginning in the 1970s the radio astronomy methods very long baseline interferometry (VLBI) and pulsar timing overtook optical instruments for the most precise astrometry.

To create a horoscope, an astrologer first has to ascertain the exact time and place of the subject's birth, or the initiation of an event. The local standard time (adjusting for any daylight saving time or war time) is then converted into Greenwich Mean Time or Universal Time at that same instant. The astrologer then has to convert this into the local sidereal time at birth in order to be able to calculate the ascendant and midheaven. The astrologer will next consult a set of tables called an ephemeris, which lists the location of the Sun, Moon and planets for a particular year, date and sidereal time, with respect to the northern hemisphere vernal equinox or the fixed stars (depending on which astrological system is being used).

Two lightcurves, published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a concurring sidereal period of and hours, respectively. Each modeled lightcurve also determined two spin axes of (68.0°, 58.0°) and (253.0°, 61.0°), as well as (262.0°, 71.0°) and (47.0°, 66.0°) in ecliptic coordinates (λ, β).

Two lightcurves, published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a concurring sidereal period of and hours, respectively. Each modeled lightcurve also determined two spin axes of (123.0°, −58.0°) and (337.0°, −47.0°), as well as (115.0°, −77.0°) and (338.0°, −43.0°) in ecliptic coordinates (λ, β).

It is categorized as an S-type asteroid consisting of mainly of iron- and magnesium-silicates. This the second most common type of asteroid in the main belt. Based on analysis of the light curve, the object has a sidereal rotation period of . An ellipsoidal model of the light curve gives an /b ratio of .

Two lightcurves, published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a concurring sidereal period of and hours, respectively. Each modeled lightcurve also determined two spin axes of (104.0°, −57.0°) and (267.0°, −53.0°), as well as (294.0°, −60.0°) and (157.0°, −57.0°) in ecliptic coordinates (λ, β), respectively.

Groundtrack of QZSS geosynchronous orbit. Seen from the ground, its analemma would have a similar shape. Geosynchronous satellites revolve around the Earth with a period of one sidereal day. Seen from a fixed point on the Earth's surface, they trace paths in the sky which repeat every day, and are therefore simple and meaningful analemmas.

24-hour dials were also used on sidereal clocks. The famous Big Ben clock in London has a 24-hour dial as part of the mechanism, although it is not visible from the outside. In the 20th century, the 24-hour analog dial was adopted by radio amateurs, pilots, submariners, and for military use.

The average length of a Martian sidereal day is (88,642.663 seconds based on SI units), and the length of its solar day is (88,775.244147 seconds). The corresponding values for Earth are currently and , respectively. This yields a conversion factor of 1.02749125170 days/sol. Thus Mars's solar day is only about 2.7% longer than Earth's.

Two lightcurves, published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a concurring sidereal period of () and () hours, respectively. Each modeled lightcurve also determined two spin axes of (213.0°, −66.0°) and (76.0°, −49.0°), as well as (282.0°, −79.0°) and (114.0°, −45.0°) in ecliptic coordinates (λ, β), respectively.

Two lightcurves, published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a concurring sidereal period of () and () hours, respectively. Each modeled lightcurve also determined two spin axes of (93.0°, −71.0°) and (277.0°, −35.0°), as well as (56.0°, −78.0°) and (255.0°, −57.0°) in ecliptic coordinates (λ, β), respectively.

The anomalistic year is the time span between successive closest approaches to the Sun. This may be calculated in the same manner as the sidereal year, but the mean anomaly is used. and travels in doing so,Jean Meeus, Astronomical Algorithms (Richmond, VA: Willmann-Bell, 1998) 238. The formula by Ramanujan is accurate enough.

'Aquarius (') is the eleventh astrological sign in the Zodiac, originating from the constellation Aquarius. Under the tropical zodiac, the Sun is in the Aquarius sign between about January 21 and about February 20, while under the sidereal Zodiac, the sun is in Aquarius from approximately February 15 to March 14, depending on the leap year.

The Sagnac effect is employed in current technology. One use is in inertial guidance systems. Ring laser gyroscopes are extremely sensitive to rotations, which need to be accounted for if an inertial guidance system is to return accurate results. The ring laser also can detect the sidereal day, which can also be termed "mode 1".

The following derivation is exclusively for motion in east–west or west–east direction. Notation: : a_u is the total centripetal acceleration when moving along the surface of the Earth. : a_s is the centripetal acceleration when stationary with respect to the Earth. : \Omega is the angular velocity of the Earth: one revolution per Sidereal day.

During this period, he played with an alternating ensemble of drummers, percussionists, electronic musicians, and dancers including Lana Guerra (aka Power Circus), Stephen Schieberl (aka Let's Go Outside, aka LGO, aka Demogorgon), Ryan Olson, Noah Mickens, Jonathan Howitt, Daniel Henderson, Marshall Serna, Ashkelon Sain, Lucretia Renee, Barrett Clark (aka Sidereal Oscillations), and many others.

The spectrum of 89 Julia shows the signature of silicate rich minerals with possible indications of an abundant calcic clinopyroxene component. It is classified as an S-type asteroid. The asteroid has an estimated diameter of . Photometry from the Oakley Observatory during 2006 produced a lightcurve that indicated a sidereal rotation period of with an amplitude of in magnitude.

Modeled photometric data from the Lowell Photometric Database (LPD) and WISE thermal data, gave a concurring sidereal rotation period of 8.57412 hours. Each modeled lightcurve also determined the object's spin axes. Durech gives only one pole, namely (7.0°, −59.0°), while Hanus determined two lower rated poles at (336.0°, −70.0°) and (72.0°, −56.0°) in ecliptic coordinates (λ, β).

Several rotational lightcurve of Lomonosowa have been obtained from photometric observations since the 1980s. Lightcurve analysis gave a rotation period between 24.482 and 24.71 hours with a brightness amplitude of 0.45 to 0.63 magnitude (). The asteroid's lightcurve has also been modeled using photometric observations from various sources. Modelling gave a concurring sidereal period of 24.4845 and 24.4846 hours.

A rotational lightcurve analysis by Czech astronomer Petr Pravec in 2007 rendered a rotation period of hours with a high brightness amplitude of 1.13 in magnitude (). A modeled lightcurves using photometric data from various sources, gave a sidereal period of hours and two spin axes of (123.0°, −51.0°) and (314.0°, −60.0°) in ecliptic coordinates (λ, β).

He carried out extensive studies of the Milky Way and was the discoverer of evidence for galactic rotation. Kapteyn was also among the first to suggest the existence of dark matter using stellar velocities as early as 1922.Kapteyn, Jacobus Cornelius (1922). "First attempt at a theory of the arrangement and motion of the sidereal system".

The Tamil calendar is a sidereal Hindu calendar used by the Tamil people of the Indian subcontinent.S.K. Chatterjee, Indian Calendric System, Publications Division, Ministry of Information and Broadcasting, Government of India, 1998Sewell, Robert and Dikshit, Sankara B.: The Indian Calendar – with tables for the conversion of Hindu and Muhammadan into a.d. dates, and vice versa. Motilal Banarsidass Publ.

To maximise the dwell time the eccentricity, the differences in altitudes of the apogee and perigee, had to be large. However, the perigee needed to be far enough above the atmosphere to avoid drag, and the orbital period needed to be approximately half a sidereal day. These two factors constrained the eccentricity to become approximately 0.737.

In 2011, a modeled lightcurve using data from the Uppsala Asteroid Photometric Catalogue and other sources gave a concurring sidereal period 3.83359 hours, as well as two poles at (46.0°, 10.0°) and (242.0°, 52.0°) in ecliptic coordinates (λ, β) (). Brian Warner also determined two spin axes at (40.0°, 18.0°) and (250.0°, 71.0°) using his data set from 2008 ().

He has published three collections of poetry: This, Snaring Heaven, and The Meaning of Flight and three novels: Shifts, Griffri, and Sidereal Time. All are published by Seren Books. A children's book in Welsh, Nadolig Bob Dydd, was published in 2000 by Gomer Press, Llandysul, Ceredigion. Meredith has also translated Mihangel Morgan's novel Melog from Welsh into English.

Calculations were then performed to convert sidereal time to local standard time. A second clock keeping standard time was equipped with a telegraphics break circuit mechanism to automatically generate the time signals. These precision clocks were known as astronomical regulators. Timekeeping instruments used at Ladd include regulators made by Robert Molyneux, Edward Howard, Hezekiah Conant, and Sigmund Riefler.

The Surya Siddhanta bridges this difference by juxtaposing the four solstitial and equinotial points with four of the twelve boundaries of the rashis. The complement of Uttarayana is Dakshinayana, i.e. the period between Karka sankranti and Makara Sankranti as per the sidereal zodiac and between the Summer solstice and Winter solstice as per the tropical zodiac.

The Gaussian year is the sidereal year for a planet of negligible mass (relative to the Sun) and unperturbed by other planets that is governed by the Gaussian gravitational constant. Such a planet would be slightly closer to the Sun than Earth's mean distance. Its length is: : days (365 d 6 h 9 min 56 s).

Bob's team at Macquarie Island and Mawson Station provided new information about the nature and source of cosmic rays. Specifically, his team reaffirmed that the rays primary source was from 'storms' on the Sun, and suggested that a small proportion of these rays had sidereal rather than solar periodicity. This important finding implied a Galactic or extra-galactic origin.

As a result of this nodal precession, the time for the Sun to return to the same lunar node, the eclipse year, is about 18.6377 days shorter than a sidereal year. The number of solar orbits (years) during one lunar nodal precession period equals the period of orbit (one year) divided by this difference, minus one: − 1\.

The tertiary and fifth component, Zeta Piscium C, is a magnitude 12.2 star at an angular separation 1.0 arc seconds from component B. Together the star system has an apparent magnitude of +4.9.John Pratt's stars re-publication by Dr J.P. Pratt (Doctor of Astronomy, University of Arizona) of sidereal coordinate data. Note: possibly a non-book published source.

Universal time (UT1) tracks the Earth's rotation in time, which performs one revolution in about 24 hours. The Earth's rotation is uneven, so UT is not linear with respect to atomic time. It is practically proportional to the sidereal time, which is also a direct measure of Earth rotation. The excess revolution time is called length of day (LOD).

Rutgers equipped the observatory with "a 6.5-inch equatorial refracting telescope, a meridian circle with four-inch object glass for transit observations, a sidereal clock, a mean solar clock...chronograph, repeating circle, and other instruments."Murray, David. Hand-Book of the Grounds and Buildings and the Memorials, Portraits and Busts of Rutgers College. Rutgers College Publication No. 11.

In the special case of a geostationary orbit, the ground track of a satellite is a single point on the equator. In the general case of a geosynchronous orbit with a non-zero inclination or eccentricity, the ground track is a more or less distorted figure-eight, returning to the same places once per sidereal day.

The 15th century Italian Renaissance philosopher Giovanni Pico della Mirandola published a massive attack on astrological predictions, but he did not object to all of astrology and he commented on the position of the vernal point in his day. Pico was aware of the effects of precession of the equinoxes and knew that the first point of Aries no longer existed in the constellation of Aries. Pico not only knew that the vernal point had shifted back into Pisces, he stated that in his time, the vernal point (zero degrees tropical Aries) was located at 2 degrees (sidereal) Pisces. This suggests that by whatever method of calculation he was employing, Pico expected the vernal point to shift into (sidereal) Aquarius age 144 years later as a one degree shift takes 72 years.

For this reason, to simplify the description of Earth's orientation in astronomy and geodesy, it was conventional to chart the positions of the stars in the sky according to right ascension and declination, which are based on a frame that follows Earth's precession, and to keep track of Earth's rotation, through sidereal time, relative to this frame as well. In this reference frame, Earth's rotation is close to constant, but the stars appear to rotate slowly with a period of about 25,800 years. It is also in this reference frame that the tropical year, the year related to Earth's seasons, represents one orbit of Earth around the Sun. The precise definition of a sidereal day is the time taken for one rotation of Earth in this precessing reference frame.

Sequences of transits usually repeat every 243 years. After this period of time Venus and Earth have returned to very nearly the same point in their respective orbits. During the Earth's 243 sidereal orbital periods, which total 88,757.3 days, Venus completes 395 sidereal orbital periods of 224.701 days each, equal to 88,756.9 Earth days. This period of time corresponds to 152 synodic periods of Venus. The pattern of 105.5, 8, 121.5 and 8 years is not the only pattern that is possible within the 243-year cycle, because of the slight mismatch between the times when the Earth and Venus arrive at the point of conjunction. Prior to 1518, the pattern of transits was 8, 113.5 and 121.5 years, and the eight inter-transit gaps before the AD 546 transit were 121.5 years apart.

Apsidal precession occurs when the direction of the major axis of the Moon's elliptic orbit rotates once every 8.85 years. The second kind of precession of the Moon's orbit is that of the major axis of the Moon's elliptic orbit (the line of the apsides from perigee to apogee), which precesses eastward by 360° in approximately 8.85 years. This is the reason that an anomalistic month (the period the Moon moves from the perigee to the apogee and to the perigee again) is longer than the sidereal month (the period the Moon takes to complete one orbit with respect to the fixed stars). This apsidal precession completes one rotation in the same time as the number of sidereal months exceeds the number of anomalistic months by exactly one, after about 3,233 days (8.85 years).

It was his first and only asteroid discovery. It is named after the goddess Freyja in Norse mythology. The sidereal orbital period of this asteroid is commensurable with that of Jupiter, which made it useful for ground-based mass estimates of the giant planet. A shape model for the asteroid was published by Stephens and Warner (2008), based upon lightcurve data.

In such cases, international collaborations are highly useful with each observatory covering a different section of the lightcurve. In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from a large collaboration of individual observers (such as above). The study also determined two spin axes of (344.0°, 27.0°) and (164.0°, 8.0°) in ecliptic coordinates (λ, β).

These results supersede the asteroid's 2016 modeled spin axes and lightcurve with a sidereal period of hours based on data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers lead by Czech astronomers Josef Hanuš and Josef Ďurech, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys .

In 2004, a rotational lightcurve of Royer was obtained from photometric observations by Brazilian and Argentine astronomers. Lightcurve analysis gave a rotation period of 3.866 hours with a brightness amplitude of 0.44 magnitude (). In 2016, a modeled lightcurves using photometric data from various sources, rendered a sidereal period of 3.88494 and two spin axes of (258.0°, 74.0°) and (54.0°, 37.0°) in ecliptic coordinates.

The east wing contains an intact meridian transit telescope and sidereal pendulum clock. The house is a two-story brick dwelling with a broad range of intact, late Victorian eclectic features. See also: Brooks was a Professor of Astronomy at Hobart College, which owned the observatory until the late 20th century It was listed on the National Register of Historic Places in 2008.

Sidereal clock acquired by George Shuckburgh He made a series of astronomical observations and an ephemeris, which he published in twelve volumes between 1774 and 1797. In 1791 the Shuckburgh telescope was installed at his private observatory in Warwickshire, England. Included among his observations were measurements of lunar surface features. The crater Shuckburgh on the Moon is named after him.

This is an aging, metal-poor giant star with a stellar classification of K1 III. It is about 9.3 billion years old with 94% of the mass of the Sun. Having exhausted the supply of hydrogen at its core, the star cooled and expanded to 23 times the Sun's radius. The star is spinning slowly, taking to complete its sidereal rotation.

This is commonly seen in astronomical clocks of the period. The small golden star shows the position of the vernal equinox, and sidereal time can be read on the scale with golden Roman numerals. The zodiac is on the 366-tooth gear inside the machine. This gear is connected to the sun gear and the moon gear by a 24-tooth gear.

Note that right ascension, as used by astronomers, is 360° minus the sidereal hour angle. The final characteristic provided in the tables and star charts is the star's brightness, expressed in terms of apparent magnitude. Magnitude is a logarithmic scale of brightness, designed so that a body of one magnitude is approximately 2.512 times brighter than a body of the next magnitude.

Lewis, James R, The astrology book: the encyclopedia of heavenly influences, p.71. Visible Ink Press, 2003. . His enthusiasm for sidereal astrology was resisted by other members; in March 1961 he resigned to found Spica, the quarterly journal he published until October 1974. This publication was a major driving force behind the western siderealist movement in the second half of the 20th century.

Because of its proximity to the pole, Deneb never sets in nearly all of Mars's northern hemisphere. Except in areas close to the equator, Deneb permanently circles the North pole. The orientation of Deneb and Sadr would make a useful clock hand for telling sidereal time. Mars's north celestial pole is also only a few degrees away from the galactic plane.

The club conducts three major events every year. In the spring the club hosts Astronomy Day and in the fall Star Gaze. Member volunteers bring telescopes for public solar and sidereal viewing and a program in the afternoon features guest speakers presenting topics of general astronomical interest. Every month there is public viewing at C.M. Crockett park in Fauquier County, Virginia.

Good results are produced by favourable planetary positions, and by benefic conjunctions and aspects, if not, unfavourable, mixed or evil results are produced. In Hindu astrology, which is sidereal and takes cognisance of nine planets - the seven afore-mentioned and the two Lunar Nodes Rahu and Ketu, three systems are followed, namely, Parashari, Jaimini and Tajika. Indian astrologers favour the Parashari System.

Throughout the year the star will rise approximately four minutes earlier each successive sunrise. Eventually the star will return to its same relative location at sunrise. This length of time can be called an observational year. Stars that reside close to the ecliptic or the ecliptic meridian will on average exhibit observational years close to the sidereal year of 365.2564 days.

A modeled lightcurve gave a concurring sidereal period of 5.94819 hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (183.0°, −50.0°) and (41.0°, −39.0°) in ecliptic coordinates (λ, β).

Edred Thorsson, Futhark: A Handbook of Rune Magic, Weiser Books, 1984, p. 15. Edred Thorsson, Rune might: secret practices of the German rune magicians, Llewellyn's Teutonic magick series, 1989. Edred Thorsson, The Truth About Teutonic Magick, Llewellyn's vanguard series, 1994. Later also: L. E. Camp, A Handbook of Armanen Runic-Wisdom: History, World- View, Rune-Yoga, Divination, the Sidereal Pendulum and the Runic-Zodiac, 2005.

Modelling gave a concurring (sidereal) period of 4.679100, 4.679102 and 4.67911 hours. The studies determined two spin axis in ecliptic coordinates (λ, β): (73.0°, −54.0°) and (198.0°, −55.0°), as well as (72.0°, −59.0°) and (207.0°, −51.0°). Modeling also confirmed that the body is a slightly elongated ellipsoid, and revealed that it is rotating along the smallest axis and that it has an almost homogeneous surface.

Also top quark pairs have been examined in the D0 experiment (2012). They showed that the cross section production of these pairs doesn't depend on sidereal time during Earth's rotation. Lorentz violation bounds on Bhabha scattering have been given by Charneski et al. (2012). They showed that differential cross sections for the vector and axial couplings in QED become direction dependent in the presence of Lorentz violation.

In the 16th century Copernicus put forward a heliocentric cosmology. Erasmus Reinhold used Copernicus' theory to compute the Prutenic Tables in 1551, and gave a tropical year length of 365 solar days, 5 hours, 55 minutes, 58 seconds (365.24720 days), based on the length of a sidereal year and the presumed rate of precession. This was actually less accurate than the earlier value of the Alfonsine Tables.

Because of Gliese 581g's proximity to its parent star, it is predicted to be tidally locked to Gliese 581. Just as Earth's Moon always presents the same face to the Earth, the length of Gliese 581g's sidereal day would then precisely match the length of its year, meaning it would be permanently light on one half and permanently dark on the other half of its surface.

In celestial navigation, the convention is to measure in degrees westward from the prime meridian (Greenwich hour angle, GHA), from the local meridian (local hour angle, LHA) or from the first point of Aries (sidereal hour angle, SHA). The hour angle is paired with the declination to fully specify the location of a point on the celestial sphere in the equatorial coordinate system.Explanatory Supplement (1992), p. 724.

Eccentricity varies primarily due to the gravitational pull of Jupiter and Saturn. However, the semi-major axis of the orbital ellipse remains unchanged; according to perturbation theory, which computes the evolution of the orbit, the semi-major axis is invariant. The orbital period (the length of a sidereal year) is also invariant, because according to Kepler's third law, it is determined by the semi-major axis.

Therefore, the Moon takes a little longer to return to perigee than to return to the same star. A draconic month is shorter than a sidereal month because the nodes move in the opposite direction as the Moon is orbiting the Earth, one revolution in 18.6 years. Therefore, the Moon returns to the same node slightly earlier than it returns to the same star.

At culmination, the object contacts the upper meridian and reaches its highest point in the sky. An object's right ascension and the local sidereal time can be used to determine the time of its culmination (see hour angle). The term meridian comes from the Latin meridies, which means both "midday" and "south", as the celestial equator appears to tilt southward from the Northern Hemisphere.

The old observatory was made into a library and then torn down to make room for Laird Hall in 1905. The observatory acquired a sidereal clock in 1910. In 1922 Carleton professor Edward Fath constructed one of the nation's first photoelectric photometers in Goodsell. The time service was continued until 1931 and the study of astronomy was prominent at Carleton well into the 20th century.

In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (160.0°, 23.0°) and (353.0°, 24.0°) in ecliptic coordinates (λ, β).

A star clock (or nocturnal) is a method of using the stars to determine the time. This is accomplished by measuring the Big Dipper's position in the sky based on a standard clock, and then employing simple addition and subtraction. This method requires no tools; others use an astrolabe and a planisphere. A clock's regulator can be adjusted so that it keeps the Mean Sidereal Time rate.

Theta Capricorni, Latinized from θ Capricorni, is a white-hued star in the southern constellation of Capricornus, 0.58° south of the ecliptic.John Pratt's stars re-publication by Dr J.P. Pratt (Doctor of Astronomy, University of Arizona) of sidereal coordinate data. Note: possibly a non-book published source. Sometimes, this star is called by the name Dorsum, meaning the back (of the goat) in Latin.

Setting circles consist of two graduated disks attached to the axes – right ascension (RA) and declination (DEC) – of an equatorial mount. The RA disk is graduated into hours, minutes, and seconds. The DEC disk is graduated into degrees, arcminutes, and arcseconds. Since the RA coordinates are fixed onto the celestial sphere, the RA disk is usually driven by a clock mechanism in sync with sidereal time.

'Scorpio (') is the eighth astrological sign in the Zodiac, originating from the constellation of Scorpius. It spans 210°–240° ecliptic longitude. Under the tropical zodiac (most commonly used in Western astrology), the Sun transits this sign on average from October 23 to November 22. Under the sidereal zodiac (most commonly used in Hindu astrology), the Sun is in Scorpio from approximately November 16 to December 15.

In sidereal and tropical astrology (including sun sign astrology), a 12-sign zodiac is used based on dividing the ecliptic into 12 equal parts rather than the IAU constellation boundaries. That is, astrological signs do not correspond to the constellations which are their namesakes, particularly not in the case of the tropical system where the divisions are fixed relative to the equinox, moving relative to the constellations.

Uttara Ashadha (lit. "latter victory", "latter unconquered") is the twenty- first of the 27 Nakshatra (constellations) in Hindu astrology. It is situated on the lower part of Lyra and spans from 26°40" in Sagittarius to 10°00" in Capricorn in the sidereal Vedic zodiac. It has 4 quarters (padas), the first one falls in Sagittarius and the last three padas fall in Capricorn.

A geostationary orbit can be achieved only at an altitude very close to and directly above the equator. This equates to an orbital speed of and an orbital period of 1,436 minutes, one sidereal day. This ensures that the satellite will match the Earth's rotational period and has a stationary footprint on the ground. All geostationary satellites have to be located on this ring.

Of the eight solar planets, all but Venus and Uranus have prograde rotation—that is, they rotate more than once per year in the same direction as they orbit the Sun, so the Sun rises in the east. Venus and Uranus, however, have retrograde rotation. For prograde rotation, the formula relating the lengths of the sidereal and solar days is: or, equivalently: On the other hand, the formula in the case of retrograde rotation is: or, equivalently: All the solar planets more distant from the Sun than Earth are similar to Earth in that, since they experience many rotations per revolution around the Sun, there is only a small difference between the length of the sidereal day and that of the solar day – the ratio of the former to the latter never being less than Earth's ratio of 0.997. But the situation is quite different for Mercury and Venus.

It has a 2:1 commensurability with Mars, having an orbital period double that of the planet. The orbital plane lies at an inclination of 6.0° to the plane of the ecliptic. This is a stony S-type asteroid with a cross-sectional size of 61 km, Photometry from the Oakley Observatory during 2006 produced a lightcurve that indicated a sidereal rotation period of with an amplitude of in magnitude.

The medieval astronomical theory of the trepidation of the equinoxes is often attributed to Thābit. But it had already been described by Theon of Alexandria in his comments of the Handy Tables of Ptolemy. According to Copernicus, Thābit determined the length of the sidereal year as 365 days, 6 hours, 9 minutes and 12 seconds (an error of 2 seconds). Copernicus based his claim on the Latin text attributed to Thābit.

In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (238.0°, −15.0°) and (47.0°, −35.0°) in ecliptic coordinates (λ, β).

In May 2002, a rotational lightcurve of Jeanne was obtained from photometric observations by French amateur astronomer Christophe Demeautis. Lightcurve analysis gave a rotation period of 15.18 hours with a brightness amplitude of 0.45 magnitude (). A lightcurve was also modeled using photometric data from the Lowell Photometric Database. It gave a concurring sidereal period of hours and two spin axes at (153.0°, 19°) and (338.0°, 32.0°) in ecliptic coordinates (λ, β).

In May 1983, a first rotational lightcurve of Numidia was obtained from photometric observations by American astronomer Richard Binzel. Lightcurve analysis gave a well-defined rotation period of 3.64 hours with a brightness amplitude of 0.35 magnitude (). Modeling of the asteroid's lightcurve gave a concurring sidereal period of 3.640739 and 3.640740 hours, respectively. In 2016, modeling also determined a pole of (201.0°, −62.0°) in ecliptic coordinates (λ, β).

At the bottom of the clock, two globes are located. The terrestrial globe rotates once per day, and the arc shows the division between day and night. The celestial globe shows the stars as they would appear if projected on a sphere surrounding the Earth. It rotates once in a sidereal day, but it also rotates around a second axis once in 25,800 years because of the precession of the equinoxes.

When Bardwell was not teaching, she was watching the sky for celestial events. In a volume of the Sidereal Messenger, she published her observations of a meteor shower radiating from the constellation Andromeda. She also published detailed observations of the Leonid meteor shower, including a chart of the Leonid Radiant in Popular Astronomy. While these observations were not new discoveries, they helped confirm which radiants meteors originated from.

In 2014, Pilcher revisited Paeonia at his Organ Mesa Observatory and measured a refined period of 7.9971 hours with an amplitude of 1.00 magnitude (), a strong indication for an elongated shape. A modeled lightcurve using photometric data from the Lowell Photometric Database was published in 2016. It gave an identical sidereal period of 7.9971 hours, as well as a spin axis at (155.0°, −50.0°) in ecliptic coordinates (λ, β).

The astronomy and the astrology of ancient India (Jyotisha) is based upon sidereal calculations, although a tropical system was also used in a few cases. Alchemy (Rasaśāstra in Sanskrit)was popular in India. It was the Indian alchemist and philosopher Kanada who introduced the concept of 'anu' which he defined as the matter which cannot be subdivided. This is analogous to the concept of atom in modern science.

In Le Pas des songes (Following Dreams) (2001) is a collection of about two hundred of François Brousse's final poems amongst more than five thousand others written between the ages of 10 to 83. DOVESFrançois Brousse, "Colombes" (Doves) La Rosée des constellations (The Dew of Constellations). (Clamart: Ed. La Licorne Ailée, 1991) 123. Doves, oh white doves, Fluttering on the tombs, Come drink from the pavement crevasses A sidereal light.

In ancient times, the sun's entry into Aries coincided with the equinox. However, due to the earth's axial precession, the sidereal year is slightly longer than the tropical year, causing the dates to gradually drift apart. Today, the sun's entry into Aries occurs around 18 April, according to astronomical definitions. Some traditional calendars are still marked by the sun's actual movements while others have since been fixed to the Gregorian calendar.

In March 2005, a rotational lightcurve of Petropolitana was obtained from photometric observations by French amateur astronomer Pierre Antonini. Lightcurve analysis gave a rotation period of hours with a brightness variation of magnitude (). In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from a large collaboration of individual observers (such as above). The study also determined two spin axes of (217.0°, 36.0°) and (34.0°, 41.0°) in ecliptic coordinates (λ, β).

In 2013, modelling by an international study using photometric data from the US Naval Observatory, the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory and the Catalina Sky Survey gave a concurring sidereal period of hours and two spin axes at (218.0°, 34.0°) and (53.0°, 41.0°) in ecliptic coordinates (λ, β). The body's very elongated shape had already been indicated by the relatively high brightness variation measured during the direct photometric observations.

In 2013, modelling by an international study using photometric data from the US Naval Observatory, the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory and the Catalina Sky Survey gave a concurring sidereal period of hours and two spin axes of (325.0°, 23.0°) and (132.0°, 26.0°) in ecliptic coordinates (λ, β). The body's very elongated shape had already been indicated by the relatively high brightness variation measured during the direct photometric observations.

Reinhardt and Rosenblum claimed that the disproof of Whitehead's theory by tidal effects was "unsubstantiated". Chiang and Hamity argued that Reinhardt and Rosenblum's approach "does not provide a unique space-time geometry for a general gravitation system", and they confirmed Will's calculations by a different method. In 1989, a modification of Whitehead's theory was proposed that eliminated the unobserved sidereal tide effects. However, the modified theory did not allow the existence of black holes.

Geostationary orbit To an observer on Earth, a satellite in a geostationary orbit appears motionless, in a fixed position in the sky. This is because it revolves around the Earth at Earth's own angular velocity (one revolution per sidereal day, in an equatorial orbit). A geostationary orbit is useful for communications because ground antennas can be aimed at the satellite without their having to track the satellite's motion. This is relatively inexpensive.

Its sidereal rotation period (day) is roughly 16.11 hours. Because its axial tilt is comparable to Earth's, the variation in the length of its day over the course of its long year is not any more extreme. Because Neptune is not a solid body, its atmosphere undergoes differential rotation. The wide equatorial zone rotates with a period of about 18 hours, which is slower than the 16.1-hour rotation of the planet's magnetic field.

In 1917 Kapteyn's assumptions on interstellar absorption were debated. The arguments were centered around an issue with the "zone of avoidance". By 1918, he was convinced light absorption was of negligible amounts and confidently stood behind his first model for the structure of the galaxy. Kapteyn had presented his findings in his life's work, First Attempt at a Theory of the Arrangement and Motion of the Sidereal System, which was published in 1922.

The Bailey-Salgado Project (often abbreviated to BSP) is an audiovisual ensemble formed in 2010 by musician and composer Tom Bailey (Thompson Twins/Babble, International Observer) and astronomer and visual artist José Francisco Salgado. They combine music with photography, video, and motion graphics to create multimedia works that have as subject the physical world. Their first work together, a short film entitled Sidereal Motion, was previewed in Bath, England in October 2010.

Third edition, Cambridge University Press (2008). and generally falls on 14 April of the Gregorian year. 14 April marks the first day of the traditional Tamil calendar and is a public holiday in the state of Tamil Nadu, Sri Lanka and Mauritius. Tropical vernal equinox fall around 22 March, and by adding 23 degrees of trepidation (oscillation) to it, we get the Hindu sidereal or Nirayana Mesha Sankranti (Sun's transition into nirayana Aries).

Incremental dating techniques allow the construction of year-by-year annual chronologies, which can be temporally fixed (i.e., linked to the present day and thus calendar or sidereal time) or floating. Archaeologists use tree-ring dating (dendrochronology) to determine the age of old pieces of wood. Trees usually add growth rings on a yearly basis, with the spacing of rings being wider in high growth years and narrower in low growth years.

ABC-Clio instead of using the sidereal year which is used in the Bikrami calendar or the old Nanakshahi and Khalsa calendars. The amended Nanakshahi calendar was adopted in 1998Louis E. Fenech, W. H. McLeod (2014) Historical Dictionary of Sikhism. Rowman & Littlefield but implemented in 2003Knut A. Jacobsen (2008) South Asian Religions on Display: Religious Processions in South Asia and in the Diaspora. Routledge Nesbitt, Eleanor (2016) Sikhism: A Very Short Introduction.

The star is eclipsed by the sun from about 1-4 March.In the Sky Earth astronomy reference utility showing the ecliptic and relevant date as at J2000 - present Thus the star can be viewed the whole night, crossing the sky, in early September, in the current epoch. It lies 0.39 degrees south of the ecliptic.John Pratt's stars re-publication by Dr J.P. Pratt (Doctor of Astronomy, University of Arizona) of sidereal coordinate data.

The 1895 Howard regulator formerly used to ring the bell at University Hall. As a number of other observatories did in the late Ladd provided an accurate regional timekeeping service by transmitting a time signal via telegraph wire. Observations of select stars were made with the meridian circle instrument as the star transited (or crossed) the meridian. This data was then used to calibrate a high quality pendulum clock set to keep sidereal time.

They have not understood that their body and > consciousness are subjected to natural laws, more obscure than, but as > inexorable as, the laws of the sidereal world. Neither have they understood > that they cannot transgress these laws without being punished. They must, > therefore, learn the necessary relations of the cosmic universe, of their > fellow men, and of their inner selves, and also those of their tissues and > their mind. Indeed, man stands above all things.

Kailasa Candra dasa (J. K. Goodwin) (born 9 January 1951) is a spiritual and occult teacher, sidereal astrologer, and author guiding a small number of students. In 1972, he joined the International Society for Krishna Consciousness (ISKCON) in Madison, Wisconsin. After the disappearance of the founder of the Hare Krishna movement, A.C. Bhaktivedanta Swami Prabhupada, he was one of the first reformers who battled against the "ISKCON" zonal acharyas in 1978 and 1979.

Brigadier Roy Charles Whitworth George FirebraceThe Astrology Game: The Inside Story : the Truth about Astrology, Malcolm Dean, Beaufort Books, 1980, p. 210 (16 August 1889 - 10 November 1974) was a British Army officer, who served as Head of the British Military Mission in Moscow during the Second World War. He was also a sidereal astrologer, founder and editor of the journal Spica, and a co-founder of the Astrological Association of Great Britain.

In September 1981, a rotational lightcurve of Marlu was obtained from photometric observations by American astronomer Alan W. Harris. Lightcurve analysis gave a rotation period of hours with a brightness variation of magnitude (). In October 2014, Daniel A. Klinglesmith confirmed the exact same period of () hours with an amplitude of () magnitude (). In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from a large collaboration of individual observers.

In 2014 and 2017, several rotational lightcurves of were obtained from photometric observations by American astronomer Brian Warner at the Palmer Divide Station () in California. Lightcurve analysis gave a consolidated rotation period of 7.879 hours with a brightness amplitude between 0.31 and 0.64 magnitude (). In 2017, Warner also modeled the photometric data and determined a sidereal period of 7.878512 hours, as well as a spin axis of (73.0°, −50.0°) in ecliptic coordinates (λ, β).

The average duration of the day-night cycle on Mars — i.e., a Martian day — is 24 hours, 39 minutes and 35.244 seconds, equivalent to 1.02749125 Earth days. The sidereal rotational period of Mars—its rotation compared to the fixed stars—is only 24 hours, 37 minutes and 22.66 seconds. The solar day lasts slightly longer because of its orbit around the sun which requires it to turn slightly further on its axis.

This is within about 1° of the position of Polaris, so that the star would appear to trace a tiny circle in the sky each sidereal day. Due to the axial precession of Earth, true north rotates in an arc with respect to the stars that takes approximately 25,000 years to complete. Around 2101–2103, Polaris will make its closest approach to the celestial north pole (extrapolated from recent Earth precession).Meeus (1997), p. 305.

There is a common misconceptionMakar Sankranti and Uttarayana misconception and Panchang Siddhanta that Makar Sankranti marks the beginning of Uttarayana. This is because at one point in time Sayana and Nirayana zodiac were the same. Every year Sidereal and Tropical equinoxes slide by 50 seconds due to Axial precession, giving birth to Ayanamsha and causing Makar Sankranti to slide further. When equinox slides it will increase ayanamsha and Makar Sankranti will also slide.

Five synodic years is 2919.6 days. Thirteen sidereal years for Venus is 2921.1 days, and eight for Earth is 2922.05 days. The heliocentric longitude of Earth advances by 0.9856° per day, and after 2919.6 days, it has advanced by 2878°, only 2° short of eight revolutions (2880°). The 3.4° inclination of Venus's orbit is great enough to usually prevent the inferior planet from passing directly between the Sun and Earth at inferior conjunction.

He was made rector of Kildress, Co. Armagh, in 1776. He set up an observatory in Cookstown, Co.Tyrone, which included an achromatic telescope, a transit instrument and clocks for solar and sidereal time. He was a member of the Royal Irish Academy (). The astronomer royal, Nevil Maskelyne, presented Hamilton's observations of the 1782 transit of Mercury to the Royal Society, as they were considered to be superior to those made at Greenwich.

Several rotational lightcurves of Maja have been obtained from photometric observations since 1988. Analysis of the best-rated lightcurve by French amateur astronomers Maurice Audejean and Jérôme Caron from February 2011 gave a rotation period of 9.73509 hours with a brightness amplitude of 0.25 magnitude (). In 2016, a modeled lightcurve was derived from various photometric database sources, giving a concurring sidereal period of 9.73570 hours and two spin axes of (49.0°, −70.0°) and (225.0°, −68.0°) in ecliptic coordinates.

The ancient Tamil calendar was based on the sidereal year similar to the ancient Hindu solar calendar, except that months were from solar calculations, and originally there was no 60-year cycle as seen in Sanskrit calendar. The year was made up of twelve months and every two months constituted a season. With the popularity of Mazhai vizhavu, traditionally commencement of Tamil year was clubbed on April 14, deviating from the astronomical date of vadavazhi vizhavu.

It showed a period of hours with an amplitude of magnitude (). The overall amplitude suggest a rather regular shape with a ratio of 0.86 for the length of the a and b axes. In 2018, Czech astronomers Josef Ďurech and Josef Hanuš published a modeled lightcurve using photometric data from the Gaia probe's second data release. It showed a sidereal period of hours, and gave a spin axis at (354.0°, 80.0°) in ecliptic coordinates (λ, β).

23 Vulpeculae is the second brightest star in the constellation. In 1967, the first pulsar, PSR B1919+21, was discovered in Vulpecula by Jocelyn Bell, supervised by Antony Hewish, in Cambridge. While they were searching for scintillation of radio signals of quasars, they observed pulses which repeated with a period of 1.3373 seconds. Terrestrial origin of the signal was ruled out because the time it took the object to reappear was a sidereal day instead of a solar day.

In February 2005, French amateur astronomer Laurent Bernasconi obtained a rotational lightcurve of Gaby from photometric observations. It gave a rotation period of 66 hours with a brightness variation of 0.27 magnitude (). This is a longer-than average rotation, since most minor planets have a period between 2 and 20 hours (see list). In 2016, concurring sidereal periods of 67.905 and 67.911 hours were obtained from modeled photometric observations derived from the Lowell Photometric Database and other sources ().

In March 2008, a rotational lightcurve of Roberts was obtained from photometric observations at the Oakley Southern Sky Observatory in Australia. Lightcurve analysis gave a well-defined rotation period of 3.278 hours with a high brightness amplitude of 0.58 magnitude (), indicative of an elongated shape. In 2016, a modeled lightcurves using photometric data from various sources, gave a sidereal period of hours and two spin axes of (63.0°, 49.0°) and (231.0°, 49.0°) in ecliptic coordinates (λ, β).

A rotational lightcurve of Achaia was obtained from photometric observations by Czech astronomer Petr Pravec at Ondřejov Observatory in October 2007. It gave a well-defined rotation period of 60.99 hours with a brightness variation of 0.72 magnitude (). Published in 2016, two additional lightcurves were derived from modeled photometric data using various sources. They gave a sidereal rotation period of and hours, as well as a spin axis of (5.0°, −65.0°) and (20.0°, −69.0°) in ecliptic coordinates, respectively.

Astrologers use many ways to divide the Great Year into twelve astrological ages. There are two popular methods. One method is to divide the Great Year into twelve astrological ages of approximately equal lengths of around 2160 years per age based on the vernal equinox moving through the sidereal zodiac. Another method is to significantly vary the duration of each astrological age based on the passage of the vernal equinox measured against the actual zodiacal constellations.

Because of this orbit, the asteroid is classified as Aten type, named after the asteroid 2062 Aten. A further characteristic is that its mean orbital period about the Sun is exactly one sidereal year. This means that it is locked into a relationship with the Earth, since such an orbit is only stable under particular conditions. As yet only a few asteroids of this sort are known, locked into a 1:1 resonance with the Earth.

The vernal equinox point is one of the two where the ecliptic intersects the celestial equator. Analogous to terrestrial longitude, right ascension is usually measured in sidereal hours, minutes and seconds instead of degrees, a result of the method of measuring right ascensions by timing the passage of objects across the meridian as the Earth rotates. There are = 15° in one hour of right ascension, and 24h of right ascension around the entire celestial equator. Astronomical Almanac 2010, p.

Each month began with a new moon; the weeks were nine days long The month names on this artifact are expressed in symbols, based on natural phenomena and agricultural cycles.Cosmology of the ancient Balts (i.e. the sidereal month was divided into three parts). The Julian calendar was used in the Grand Duchy of Lithuania; the Gregorian calendar was adopted by the Polish-Lithuanian Commonwealth in 1586, a few years after its promulgation in 1582 by Pope Gregory XIII.

" Bishops Ring Around the Sun",by William M Davis, The Popular Science Monthly Feb 1885 – pages 471–473, Cambridge, Massachusetts, December 1885. The Warner Observatory in Rochester, New York USA awarded Kiessling in 1886 with first prize for best 3000 word essay on the topic of the “Red-Sky glows” phenomena." The Sidereal Messenger or The Monthly Review of Astronomy",conducted by William W Payne, Volume 6 1887, Page 120, Carleton College Observatory, Northfield Minn. December 1887.

In the Srimad Bhagavatam, Krishna tells Arjuna, that among the Nakshatras he is Abhijit, which remark indicates the auspiciousness of this Nakshatra.Srimad Bhagavatam, Canto 11, Chapter 16, Text/Verse 27 In the Bhagavad Gita Chapter 10 Verse 21, it is mentioned as Sasi (Moon) rather than as Abhijit. Its longitude starts from 06° 40' to 10° 53' 20 in sidereal Capricorn i.e. from the last quarter of nakshatra Uttara Ashādhā to first 1/15 th part of Shravana.

The Dhaarmik Traditions, by Kosla Vepa Hence, Abhijit nakshatra i not a regular nakshatra with four padas or quarters and thus it serves as an intercalary asterism most of the time. It is not mentioned as frequently as the other asterisms in mythology. The Moon or Chandra is said to have 27 (not 28) wives with whom he stays for one day in a sidereal lunar month. Each of the 27 asterisms is feminine: only Abhijit is masculine.

In order to measure the position of, for example, a star, the observer needs a sidereal clock in addition to the mural instrument. With the clock measuring time, a star of interest is observed with the instrument until it crosses an indicator showing that it is transiting the meridian. At this instant, the time on the clock is recorded as well as the angular elevation of the star. This yields the position in the coordinates of the instrument.

Earth at seasonal points in its orbit (not to scale) Earth orbit (yellow) compared to a circle (gray) Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi), and one complete orbit takes days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi).Jean Meeus, Astronomical Algorithms 2nd ed, (Richmond, VA: Willmann-Bell, 1998) 238. See Ellipse#Circumference. The formula by Ramanujan is accurate enough.

Available celestial objects were planets, Messier objects, and stars from 3 different catalogs, totaling to over 600 entries. Plots could be done in 9 directions, N, NE, E, SE, S, SW, W, NW and overhead (a view upwards the sky). Clicking on a star with a joystick or gamepad would give detailed information on each object, including declination, right ascension, magnitude, rising and setting times in sidereal time and Universal Time, and ranges of the year of visibility.

Cancer () is the fourth astrological sign in the Zodiac, originating from the constellation of Cancer. It spans from 90° to 120° celestial longitude. Under the tropical zodiac, the Sun transits this area between approximately June 22 and July 22, and under the sidereal zodiac, the Sun transits this area between approximately July 21 and August 9. In astrology, Cancer is the cardinal sign of the Water trigon, which is made up of Cancer, Pisces, and Scorpio.

Each of these three years can be loosely called an astronomical year. The sidereal year is the time taken for the Earth to complete one revolution of its orbit, as measured against a fixed frame of reference (such as the fixed stars, Latin , singular ). Its average duration is days (365 d 6 h 9 min 9.76 s) (at the epoch J2000.0 = January 1, 2000, 12:00:00 TT).International Earth Rotation and Reference System Service. (2010).

In sidereal astrology, the Sun currently transits the constellation of Pisces from approximately March 12 to April 18. In classical interpretations, the symbol of the fish is derived from the ichthyocentaurs, who aided Aphrodite when she was born from the sea. According to some tropical astrologers, the current astrological age is the Age of Pisces,Nicholas Campion, (1988) The Book of World Horoscopes Aquarian Press, Wellingborough while others maintain that currently it is the Age of Aquarius.

It can be established that SI seconds apply to this value by following the citation in "USEFUL CONSTANTS" to E. Groten "Parameters of Common Relevance of Astronomy, Geodesy, and Geodynamics" which states units are SI units, except for an instance not relevant to this value. Multiplying by (180°/π radians) × (86,400 seconds/day) yields , indicating that Earth rotates more than 360° relative to the fixed stars in one solar day. Earth's movement along its nearly circular orbit while it is rotating once around its axis requires that Earth rotate slightly more than once relative to the fixed stars before the mean Sun can pass overhead again, even though it rotates only once (360°) relative to the mean Sun.In astronomy, unlike geometry, 360° means returning to the same point in some cyclical time scale, either one mean solar day or one sidereal day for rotation on Earth's axis, or one sidereal year or one mean tropical year or even one mean Julian year containing exactly for revolution around the Sun.

The 28 Lunar Mansions, or more precisely lodgings () are the Chinese and East Asian form of the lunar stations. They can be considered as the equivalent to the Western zodiac, although the 28 stations reflect the movement of the Moon through a sidereal month rather than the Sun in a tropical year. In their final form, they embodied the astral forms of the Four Symbols: two real and two legendary animals important in traditional Chinese culture, such as feng shui.

Concordia (minor planet designation: 58 Concordia) is a fairly large main-belt asteroid that is orbiting the Sun with a period of 4.44 years, a semimajor axis of , and a low eccentricity of 0.043. It is classified as a C-type asteroid, meaning that its surface is very dark and it is likely carbonaceous in composition. The surface spectra displays indications of hydrated minerals created through aqueous alteration. The object is rotating with a sidereal period of and pole orientations of (, ) and (, ).

In August 2005, a rotational lightcurve of Atossa was obtained from photometric observations by French amateur astronomer Philippe Baudoin. Lightcurve analysis gave a well-defined rotation period of hours with a high brightness variation of magnitude, indicative of a non-spherical, elongated shape (). In 2011, a modeled lightcurve using data from the Uppsala Asteroid Photometric Catalogue (UAPC) and other sources gave a sidereal period hours, as well as two spin axes at (12.0°, 67.0°) and (188.0°, 69.0°) in ecliptic coordinates (λ, β).

The entrance tickets to the museum feature the astronomic dial of the Prague Astronomical Clock with the exact moment of entry to the museum, with the same data also expressed in the Old Bohemian and in the Babylonian manner. The sidereal time is also included. The entrance tickets were designed by Vojtěch Sedláček, CEO of Agentura ProVás. On 31 December 2017, the Kepler Museum in the Old Town closed after eight years, to be taken over by the National Technical Museum (NTM).

Orbiting at an altitude of approximately ; orbital radius of approximately ,, each SV makes two complete orbits each sidereal day, repeating the same ground track each day. This article from author's web site , with minor correction. This was very helpful during development because even with only four satellites, correct alignment means all four are visible from one spot for a few hours each day. For military operations, the ground track repeat can be used to ensure good coverage in combat zones.

To Spiesberger, they were just one more tool to be used by any individual magician. After the war he also wrote Der erfolgreiche Pendel-PraktikerAntiquario – Handelsplattform für antiquarische Buecher published in 1963. Although still far more readily available in its original German text, it is now also available in its 1989 English translation entitled Reveal the Power of the Pendulum.Reveal the Power of the Pendulum: Secrets of the Sidereal Pendulum, A Complete Survey of Pendulum Dowsing , it was published in England 'W.

The same ring offers, at the eastern point, the figure of the wind god Ehécatl, who with his breath propels the ship to the west. At the setting point appears the Sun of the evening twilight; at the north point, interspersed in the inscription, the sidereal stars that make constant knowledge of their position possible. Finally, in the upper part of the body, the eagle of the Mexican Coat of Arms, which recalls the origin of the ship and its strength.

In February 2012, a rotational lightcurve of Schürer was obtained from photometric observations by an international collaboration under the lead of South Korean astronomers. Lightcurve analysis gave a rotation period of hours with a brightness amplitude of 0.77 magnitude, indicative of an elongated, non-spherical shape (). A modeled lightcurve using photometric data from Gaias DR2 catalog was published in 2018. It gave a similar sidereal period of hours, as well as a spin axis at (235.0°, −26.0°) in ecliptic coordinates (λ, β).

A synodic day is the period it takes for a planet to rotate once in relation to the star it is orbiting (its primary body). The synodic day is distinguished from the sidereal day, which is one complete rotation in relation to distant stars. This is different from the duration of a synodic day because the revolution of the body around its parent star would cause a single "day" to pass relative to a star, even if the body did not rotate itself.

The horizontal, or altitude-azimuth, system is based on the position of the observer on Earth, which revolves around its own axis once per sidereal day (23 hours, 56 minutes and 4.091 seconds) in relation to the star background. The positioning of a celestial object by the horizontal system varies with time, but is a useful coordinate system for locating and tracking objects for observers on Earth. It is based on the position of stars relative to an observer's ideal horizon.

Zodiac symbols (Vedic astrology) on the terrace of a temple in Kanipakam, Andhra Pradesh Sidereal (Vedic) astrology shares the same system as Western astrology of linking zodiac signs to elements. In addition, in Vedic thought each of the five planets are linked to an element (with space as the fifth). It was said in the Veda that everything emanated from the one basic vibration of "Om" or "Aum." From "Om" the five elemental vibrations emerged representing the five different tattwas (or elements).

The asteroid has an ambiguous lightcurve. While a lightcurve, obtained at the Palomar Transient Factory in September 2013, gave a rotation period of 108.259 hours with a brightness amplitude of 0.48 magnitude (), another lightcurve modeled from combined dense and sparse photometry gave a sidereal period of 16.5931 hours.(). If the first result were correct, Sofala would be one of few hundred known slow rotators with a period above 100 hours. The Lightcurve Data Base, however, adopts the shorter period from the modeled lightcurve.

This was a good approximation, but not a perfect one, since 59 (sidereal) years are equal to 21550.1 days, while 730 (synodical) months equal 21557.3 days. The difference therefore amounts to seven days. In addition there are the interfering variations in the lunar orbit. However, a 59-year period had the advantage that it corresponded quite closely to an integer number of orbital revolutions of several planets around the Sun, which meant that their relative positions also repeated each Great Year cycle.

The orientation (rather than the angle) of Earth's axis also changes over time, precessing around in a complete circle over each 25,800 year cycle; this precession is the reason for the difference between a sidereal year and a tropical year. Both of these motions are caused by the varying attraction of the Sun and the Moon on Earth's equatorial bulge. The poles also migrate a few meters across Earth's surface. This polar motion has multiple, cyclical components, which collectively are termed quasiperiodic motion.

The astronauts controlled the reentry, creating drag and lift by rotating the capsule. Due to a computing error, the crew landed 80 miles (130 kilometers) short of the planned landing point in the Atlantic Ocean. Although the computer had worked perfectly, a programmer had entered the rate of the Earth's rotation as 360° per 24 hours instead of 360.98° See Sidereal day. The Gemini 5 mission was supported by the following U.S. Department of Defense resources: 10,265 personnel, 114 aircraft and 19 ships.

Lightcurve inversion also modeled the body's shape and poles. In 2013, modelling by an international study using photometric data from the US Naval Observatory, the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory and the Catalina Sky Survey gave a similar sidereal period of 4.007347 hours and two spin axes of (356.0°, 68.0°) and (153.0°, 78.0°) in ecliptic coordinates (λ, β). The body's very elongated shape had already been indicated by the high brightness variation measured during the photometric observations.

The value of Gauss' constant, exactly as he derived it, had been used since Gauss' time because it was held to be a fundamental constant, as described above. The solar mass, mean solar day and sidereal year with which Gauss defined his constant are all slowly changing in value. If modern values were inserted into the defining equation, a value of would result. It is also possible to set the gravitational constant, the mass of the Sun, and the astronomical unit to 1.

A lunar station, also called a lunar mansion or lunar house, is a segment of the ecliptic through which the Moon passes in its orbit around the Earth. The concept was used by several ancient cultures as part of their calendrical system. In general, though not always, the zodiac is divided into 27 or 28 segments relative to the fixed stars – one for each day of the lunar month. (A sidereal month lasts about 27.3 days.) The Moon's position is charted with respect to those fixed segments.

Additional observation by the Spanish OBAS group gave a period of hours with an amplitude of magnitude (). In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (276.0°, 70.0°) and (90.0°, 39.0°) in ecliptic coordinates (λ, β).

Leap Seconds. (1999). Time Service Department, United States Naval Observatory. The two kinds of solar time (apparent solar time and mean solar time) are among the three kinds of time reckoning that were employed by astronomers until the 1950s. (The third kind of traditional time reckoning is sidereal time, which is based on the apparent motions of stars other than the Sun.)For the three kinds of time, see (for example) the explanatory section in the almanac Connaissance des Temps for 1902, page 759 .

6 of Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac (Washington, DC: 1898), pp. 10-11. However, the mean tropical year is not suitable as a unit of measurement because it varies from year to year by a small amount, days according to Newcomb. In contrast, the Julian year is defined in terms of SI units so is as accurate as those units and is constant. It approximates both the sidereal year and the tropical year to about ±0.008 days.

The authors enter at some length on the sidereal period, or Yugas of the Hindus, which became known to the Arabs by a translation of the Siddhanta." # Love of the soul for the Creator. # Resurrection and immortality of the soul; this risala has especial emphasis on the ascension of the soul, and Davidson says: "In this the whole system laid down in the Cyclopaedia culminates." # On motion, and on the Cosmological argument # On cause and effect # "On the nature of simple and compound bodies.

Karl Spiesberger (29 October 1904 – 1 January 1992) was a German mystic, occultist, Germanic revivalist and Runosophist. He is most well known for his revivalism and usage of the Sidereal Pendulum for divination and dowsing and for his anti-racialist stance and revivalist usage of the Armanen Futharkh runic system after the second world war, removing its negative connotations. During his involvement with the Fraternitas Saturni Spiesberger was also known as Frater Eratus. Under this name he published several articles in the Blätter für angewandte okkulte Lebenskunst.

As of 2020, Malbils effective size, its composition and albedo remain unknown. Data from photometric observation gave a modeled sidereal rotation period of 7.5498 hours and two spin axes at (253°, −74°) and (127.0°, −69.0°) in ecliptic coordinates (λ, β). The modeling suggests that the asteroid is rather elongated in shape. Based on a magnitude-to-diameter conversion, its generic diameter is between 5 and 12 kilometer for an absolute magnitude of 13.4, and an assumed albedo in the range of 0.05 to 0.25.

Given enough time, this would create a mutual tidal locking between Earth and the Moon. The length of the Earth's day would increase and the length of a lunar month would also increase. The Earth's sidereal day would eventually have the same length as the Moon's orbital period, about 47 times the length of the Earth's day at present. However, Earth is not expected to become tidally locked to the Moon before the Sun becomes a red giant and engulfs Earth and the Moon.

The meditation is aided by extensive symbology, mantras, diagrams, models (deity and mandala). The practitioner proceeds step by step from perceptible models, to increasingly abstract models where deity and external mandala are abandoned, inner self and internal mandalas are awakened. These ideas are not unique to Hindu and Buddhist traditions. Similar and overlapping concepts emerged in other cultures in the East and the West, and these are variously called by other names such as subtle body, spirit body, esoteric anatomy, sidereal body and etheric body.

It arrived sometime in the late 18thcentury, potentially from the first or second generation of Spanish conquistadores. Even though the last date entry in the book is from several centuries before its relocation, the book was likely used and added to until just before the conquerors took it. About 65 per cent of the pages in the Dresden Codex contain richly illustrated astronomical tables. These tables focus on eclipses, equinoxes and solstices, the sidereal cycle of Mars, and the synodic cycles of Mars and Venus.

These two crossings rotate once in 18.5 years (known as the Saros cycle) and are indicated by the hand with the Ω (omega) sign. Eclipses occur when the three hands overlap, which typically happens two or three times a year; they overlap in nearly exactly the same position every 18.5 years. In the centre of the dial, a spherical slice of the Earth is located. It rotates counter-clockwise once in a sidereal day, and is used to indicate where the eclipse is visible.

The eccentricity of the orbit is based on the differences in altitudes of its apogee and perigee. To maximise the amount of time that the satellite spends over the apogee, the eccentricity should be set as high as possible. However, the perigee needs to be high enough to keep the satellite substantially above the atmosphere to minimize drag (~600km), and the orbital period needs to be kept to approximately half a sidereal day (as above). These two factors constrain the eccentricity, which becomes approximately 0.737.

Nearly 500 pages long, it manages to be at once comprehensive, succinct and readable. The book covers physical, descriptive, sidereal, and practical aspects of astronomy, along with a treatise on globes, a history of astronomy, an astronomical dictionary, notes and an index. Her treatment of the subject indicates that Hannah Bouvier was widely read, with broad knowledge of her field and considerable skill in organizing and presenting her material. The book includes over 200 engravings, many of which may have been prepared by Bouvier herself.

The Earth Rotation Angle (ERA) measures the rotation of the Earth from an origin on the celestial equator, the Celestial Intermediate Origin, that has no instantaneous motion along the equator; it was originally referred to as the non-rotating origin. ERA replaces Greenwich Apparent Sidereal Time (GAST). The origin on the celestial equator for GAST, called the true equinox, does move, due to the movement of the equator and the ecliptic. The lack of motion of the origin of ERA is considered a significant advantage.

Arnold and Dent have just completed another of those beautiful > specimens of art, in the shape of a pocket chronometer, showing at once both > mean and sidereal time. This is the fourth of these machines that has been > made. In an article entitled Hints on Chronometers appearing in Nautical Magazine and dated February 1833, Dent reveals that chronometer No. 633 was sent with 21 other chronometers to Captain FitzRoy on board in 1831. In fact, several of these chronometers were by Arnold and Dent.

In 2011, two rotational lightcurves of Somalia were obtained from photometric observations by French amateur astronomer René Roy, and by astronomers at the Bassano Bresciano Observatory () in Italy. Lightcurve analysis gave a rotation period of 6.910 and 6.913 hours with a brightness amplitude of 0.40 and 0.45 magnitude, respectively (). In 2016, a modeled lightcurve was derived from various photometric database sources, giving a concurring sidereal period of 6.90907 hours. The modelled lightcurve also determined two spin axis of (297.0°, 42.0°) and (128.0°, 47.0°) in ecliptic coordinates.

In the early 2000s, a rotational lightcurve of Tirela was obtained from photometric observations by a group of Hungarian astronomers. Lightcurve analysis gave a rotation period of 13.356 hours with a brightness amplitude of 0.55 magnitude (), superseding the result from a previous observation that gave a period of 8 hours. A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database, gave a concurring sidereal period of hours, as well as two spin axis of (58.0°, −80.0°) and (297.0°, −41.0°) in ecliptic coordinates (λ, β).

Thus the sidereal day is shorter than the stellar day by about 8.4 ms. Apart from meteors within the atmosphere and low-orbiting satellites, the main apparent motion of celestial bodies in Earth's sky is to the west at a rate of 15°/h = 15'/min. For bodies near the celestial equator, this is equivalent to an apparent diameter of the Sun or the Moon every two minutes; from Earth's surface, the apparent sizes of the Sun and the Moon are approximately the same.

Songkran is a term derived from the Sanskrit word, ' (or, more specifically, ') and used to refer to the traditional New Year celebrated in Thailand, Laos, Cambodia, Myanmar, Sri Lanka, parts of northeast India, parts of Vietnam and Xishuangbanna, China. It begins when the sun transits the constellation of Aries, the first astrological sign in the Zodiac, as reckoned by sidereal astrology. It is related to the equivalent Hindu calendar-based New Year festivals in most parts of South Asia which are collectively referred to as Mesha Sankranti.

In the end, it seemed best to display both the natural cycles and some of the current cultural cycles. The center of the clock will show a star field, indicating both the sidereal day and the precession of the zodiac. Around this will be a display showing the positions of the Sun and the Moon in the sky, as well as the phase and angle of the Moon. Outside this will be the ephemeral dial, showing the year according to our current Gregorian calendar system.

Also known as the Axial system, or Equatorial system, it divides the celestial equator in twelve 30° sectors (starting at the local meridian) and projects them on to the ecliptic along the great circles containing the North and South celestial poles. The intersections of the ecliptic with those great circles provide the house cusps. The 10th house cusp thus equals the Midheaven, but the East Point (also known as Equatorial Ascendant) is now the first house's cusp. Each house is exactly 2 sidereal hours long.

Published in 2018, thermophysical modeling of Malzovia from thermal data obtained from the Wide- field Infrared Survey Explorer (WISE) gave a sidereal period of () and two spin axes at (53.0°, 37.0°) and (242.0°, 46.0°) in ecliptic coordinates (λ, β). Previously, two lightcurves published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a period of () and hours, respectively. Each modeled lightcurve also determined two poles at (53.0°, 37.0°) and (242.0°, 46.0°), as well as (55.0°, 46.0°) and (246.0°, 55.0°), respectively.

Richard Anthony Proctor (23 March 1837 – 12 September 1888) was an English astronomer. He is best remembered for having produced one of the earliest maps of Mars in 1867 from 27 drawings by the English observer William Rutter Dawes. His map was later superseded by those of Giovanni Schiaparelli and Eugène Antoniadi and his nomenclature was dropped (for instance, his "Kaiser Sea" became Syrtis Major Planum). He used old drawings of Mars dating back to 1666 to try to determine the sidereal day of Mars.

Satellites in geostationary orbit. A geosynchronous satellite is a satellite in geosynchronous orbit, with an orbital period the same as the Earth's rotation period. Such a satellite returns to the same position in the sky after each sidereal day, and over the course of a day traces out a path in the sky that is typically some form of analemma. A special case of geosynchronous satellite is the geostationary satellite, which has a geostationary orbit – a circular geosynchronous orbit directly above the Earth's equator.

Since 2001, a large number of rotational lightcurves of Itokawa have been obtained from photometric observations. Analysis of the best-rated lightcurve by Mikko Kaasalainen gave a sidereal rotation period of hours with a high brightness variation of 0.8 magnitude, indicative of the asteroid's non- spherical shape (). In addition, Kaasalainen also determined two spin axes of (355.0°, −84.0°) and (39°, −87.0°) in ecliptic coordinates (λ, β). Alternative lightcurve measurements were made by Lambert ( h), Lowry ( and h), Ohba ( h), Warner ( h), Ďurech ( h), and Nishihara ( h).

The first chapter "Fremde Vögel" ("Strange Birds") discusses an emerging global change to the Earth and humanity. The second chapter "Messbare und Schicksalszeit" ("Measurable and Fate Time") draws out a distinction between a scientific and an astrological conception of time and the world. The next chapters, "Humane Einteilungen" and "Siderische Einteilungen" ("Humane Classifications" and "Sidereal Classifications"), consider mankind and its place in cosmological contexts. The fifth and final chapter, "Urgrund und Person" ("Primordial Foundation and Person"), discusses the individual and its relationship with faith and religious institutions.

Several rotational lightcurves of Hoag have been obtained from photometric observations since 2007. Best-rated lightcurve by American astronomer Brian Warner at his Palmer Divide Observatory in Colorado, gave a well-defined rotation period of 2.3717 hours with a brightness amplitude of 0.12 magnitude (). In 2010, Warner also modeled a lightcurve using the data from his various photometric observations. It gave a concurring sidereal period of 2.37219 hours, as well as two spin axes at (45.0°, 45.0°) and (225.0°, 45.0°) in ecliptic coordinates (λ, β).

In November 2010, a rotational lightcurve of Alekfursenko was obtained from photometric observations made by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of hours with a brightness variation of 0.42 magnitude (). A modeled lightcurve using photometric data from the Lowell Photometric Database and from the Wide-field Infrared Survey Explorer (WISE) was published in 2018. It gave a concurring sidereal period of hours, as well as a spin axis at (−1.0°, 54.0°) in ecliptic coordinates (λ, β).

Areosynchronous orbits (ASO) are a class of synchronous orbits for artificial satellites around the planet Mars. As with all synchronous orbits, an areosynchronous orbit has an orbital period equal in length to the primary's sidereal day. A satellite in areosynchronous orbit does not necessarily maintain a fixed position in the sky as seen by an observer on the surface of Mars; however, such a satellite will return to the same apparent position every Martian day. The orbital altitude required to maintain an areosynchonous orbit is approximately .

The original reason astronomers thought it was synchronously locked was that, whenever Mercury was best placed for observation, it was always nearly at the same point in its 3:2 resonance, hence showing the same face. This is because, coincidentally, Mercury's rotation period is almost exactly half of its synodic period with respect to Earth. Due to Mercury's 3:2 spin-orbit resonance, a solar day (the length between two meridian transits of the Sun) lasts about 176 Earth days. A sidereal day (the period of rotation) lasts about 58.7 Earth days.

In May 2015, a rotational lightcurve of Mechthild was obtained from photometric observations by Brian Warner at his Palmer Divide Observatory in Colorado. Lightcurve analysis gave a rotation period of hours with a brightness amplitude of magnitude (). Alternative period determinations were made by Claes-Ingvar Lagerkvist () in March 1976, by astronomers at the Palomar Transient Factory () in January 2014, and by the Spanish group of asteroid observers, OBAS () in May 2015 (). In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from a large collaboration of individual observers (such as above).

Lightcurve-based 3D-model of Ara In June 1981, a rotational lightcurve of Ara was obtained from photometric observations by Alan Harris. Lightcurve analysis gave a rotation period of hours with a brightness variation of magnitude, indicative of an elongated shape (). Numerous observations have since confirmed this period. This includes Laurent Bernasconi (2004) and (2006), Davide Gandolfi (2006), Adam Marciniak (2009), Maurice Audejean (2010), and Richard E. Schmidt (2017). In 2017, a modeled lightcurve gave a concurring sidereal period of hours as well as a spin axis of (223.0°, −41.0°) in ecliptic coordinates (λ, β).

In September 2010, a rotational lightcurve of Ulrike was obtained from photometric observations by John Menke at the Menke Observatory. Lightcurve analysis gave a rotation period of hours with a high brightness variation of magnitude, indicative of an elongated shape (). An alternative period determination of hours with an even higher amplitude of was made by Laurent Bernasconi one month later in October 2010 (). A modeled lightcurve using photometric data from the Lowell Photometric Database gave a sidereal period of and two spin axes at (13.0°, −64.0°) and (207.0°, −60.0°) in ecliptic coordinates (λ, β).

In October 2000, a rotational lightcurve of Amelia was obtained from photometric observations by American amateur astronomer Robert A. Koff at the Thornton Observatory in Colorado. Lightcurve analysis gave a well-defined rotation period of hours with a brightness amplitude of magnitude (). In December 2006, a concurring period determination of was made by astronomers Raymond Poncy, Enric Forné, Hiromi Hamanowa, Hiroko Hamanowa and Hilari Pallarés (). In 2016, a modeled lightcurves using photometric data from various sources, rendered a concurring sidereal period of and two spin axes of (80.0°, 30.0°) and (282.0°, 30.0°) in ecliptic coordinates.

The religion of the Muisca consisted of various gods, mostly related to natural phenomena as the Sun (Sué) and his wife, the Moon; Chía, rain Chibchacum, rainbow Cuchavira and with building and feasting (Nencatacoa) and wisdom (Bochica). Their complex luni-solar calendar, deciphered by Manuel Izquierdo based on work by Duquesne, followed three different sets of years, where the sidereal and synodic months were represented. Their astronomical knowledge is represented in one of the few extant landmarks of the architecture of the Muisca in El Infiernito outside Villa de Leyva to the north of Bogotá.

Three rotational lightcurve of Di Martino have been obtained from photometric observations by French amateur astronomer Pierre Antonini and at the Palomar Transient Factory and Haute Provence Observatory (). Lightcurve analysis gave a rotation period of 5.445 hours with a consolidated brightness amplitude between 0.32 and 0.51 magnitude (), indicative of a somewhat elongated shape. In 2016, a modeled lightcurve gave a concurring sidereal period of 5.44517 hours using photometric data from a large international collaboration of astronomers. The study also determined two spin axes of (53.0°, −70.0°) and (231.0°, −75.0°) in ecliptic coordinates (λ, β).

In March 2010, a rotational lightcurve of Maupertuis was obtained from photometric observations by French amateur astronomer René Roy. Lightcurve analysis gave a well-defined rotation period of 6.7295 hours with an exceptionally high brightness amplitude of 1.22 magnitude (), indicative of a strongly elongated shape. In March 2016, a second period was published based on data from the Lowell Photometric Database. Using lightcurve inversion and convex shape models, as well as distributed computing power and the help of individual volunteers, a sidereal period of hours was derived from the database's sparse- in-time photometry data.

Table of synodic periods in the Solar System, relative to Earth: In the case of a planet's moon, the synodic period usually means the Sun-synodic period, namely, the time it takes the moon to complete its illumination phases, completing the solar phases for an astronomer on the planet's surface. The Earth's motion does not determine this value for other planets because an Earth observer is not orbited by the moons in question. For example, Deimos's synodic period is 1.2648 days, 0.18% longer than Deimos's sidereal period of 1.2624 d.

The method relies on the relatively quick movement of the moon across the background sky, completing a circuit of 360 degrees in 27.3 days (the sidereal month), or 13.2 degrees per day. In one hour it will move approximately half a degree, roughly its own angular diameter, with respect to the background stars and the Sun. Using a sextant, the navigator precisely measures the angle between the moon and another body. That could be the Sun or one of a selected group of bright stars lying close to the Moon's path, near the ecliptic.

Comparing his measurements with data from his predecessors, Timocharis and Aristillus, he concluded that Spica had moved 2° relative to the autumnal equinox. He also compared the lengths of the tropical year (the time it takes the Sun to return to an equinox) and the sidereal year (the time it takes the Sun to return to a fixed star), and found a slight discrepancy. Hipparchus concluded that the equinoxes were moving ("precessing") through the zodiac, and that the rate of precession was not less than 1° in a century.

Third generation particles have been examined for potential Lorentz violations using SME. For instance, Altschul (2007) placed upper limits on Lorentz violation of the tau of 10−8, by searching for anomalous absorption of high energy astrophysical radiation. In the BaBar experiment (2007), the D0 experiment (2015), and the LHCb experiment (2016), searches have been made for sidereal variations during Earth's rotation using B mesons (thus bottom quarks) and their antiparticles. No Lorentz and CPT violating signal were found with upper limits in the range 10−15 − 10−14 GeV.

The rear planisphere, similar in size to the one in the front but strictly circular, displays the brightest stars of the main circumpolar constellations (Ursa Major, Ursa Minor, and Cassiopeia). It is centred on the north celestial pole and, with its encircling silvered ring of 24-hour intervals, rotates once a sidereal day relative to a fixed meridian- index. Damage to the clock's mechanism was sustained during the fire of 9 July 1984; after 10 years' reparation work, vergers ceased winding it owing to inaccuracies of time-keeping.

In April 2008, a rotational lightcurve of Auricula was obtained from photometric observations by Colin Bembrick at the Mount Tarana Observatory and other observers from Australia and New Zealand. Lightcurve analysis gave a rotation period of hours with a brightness amplitude of 0.75 magnitude (), indicative of a non-spherical, elongated shape. A modeled lightcurve using photometric data from the Lowell Photometric Database was published in 2016. It gave a concurring sidereal period of hours, as well as two spin axes at (57.0°, −57.0°) and (225.0°, −85.0°) in ecliptic coordinates (λ, β).

This might sound more than sufficiently accurate for a man's lifetime, but as seen in clock No. 1, Sørnes wanted to be able to run his clocks forwards and backward in time to examine previous and coming events. Another shortcoming is that the sidereal works will slow down 1 minute in 10 years. On the other hand, the error for the Earth's rotation around the sun is only 0.7 seconds per year. This can be compared to the famous astronomical clock in Strasbourg, which has an error of maximum 2 seconds per year.

Traditional Western astrology is based on tropical astrology, which presumes an equal division of the celestial sphere along the ecliptic into twelve equal parts, starting with Aries. Sidereal astrology, at once the oldest and a recently revived astrological tradition, is more observationally oriented and uses the actual observed position of the stars and the traditional divisions of the zodiac constellations as its starting point. As a result of the precession of the equinoxes, the observed positions of the zodiac signs no longer correspond to the signs of tropical astrology.

The Maithili New Year follows the Nirayanam vernal equinox and falls on 30 April (may sometimes vary by a day) on the Gregorian year. 14 April marks the first day of the traditional Tirhuta Panchang . Tropical vernal equinox fall around 22 March, and adding 23 degrees of trepidation or oscillation to it, we get the Hindu sidereal or Nirayana Mesha Sankranti (Sun's transition into Nirayana Aries).Maithili Panchang, of Kameshwar Singh Darbhanga Sanskrit University Published from Darbhanga Hence, the Maithili calendar begins on the same date, with Baishakh as first month of the year.

Here Copernicus asserts that the motion of the equinoxes and celestial poles has not been uniform, and argues that consequently they should not be used to define the reference frame with respect to which the motions of the planets are measured, and that the periods of the various planetary motions are more accurately determinable if those motions are measured with respect to the fixed stars. He maintains that he had found the length of the sidereal year to have always been 365 days 6 hours and 10 minutes.

A Dent sidereal clock was lent by the Venus Commission. Gill telegrammed Nevill to offer the post of Government Astronomer, and Nevill sailed at 24 hours' notice on 27 October and arrived 27 November 1882. ;State of the observatory Nevill took possession of the observatory 1 December 1882 and found a thick coat of paint covered dome machinery making it immovable, the telescope had been erected prior to dome and had suffered from salt air and moved with difficulty, the polarising solar eyepiece was incompatible with telescope or accessories.

Before 1200, India had two theories of trepidation, one with a rate and another without a rate, and several related models of precession. Each had minor changes or corrections by various commentators. The dominant of the three was the trepidation described by the most respected Indian astronomical treatise, the Surya Siddhanta (3:9–12), composed but revised during the next few centuries. It used a sidereal epoch, or ayanamsa, that is still used by all Indian calendars, varying over the ecliptic longitude of 19°11′ to 23°51′, depending on the group consulted.

Many astrologers find ages too erratic based on either the vernal point moving through the randomly sized zodiacal constellations or sidereal zodiac and, instead, round all astrological ages to exactly 2000 years each. In this approach the ages are usually neatly aligned so that the Aries age is found from 2000 BC to AD 1, Pisces age AD 1 to AD 2000, the Aquarian Age AD 2000 - AD 4000, and so on.Neil Spencer, True as the Stars Above, Victor Gollancz London, 2000, p. 119 This approach is inconsistent with the precession of the equinoxes.

The Natal Observatory was initially equipped with a 200 mm Grubb equatorial refracting telescope donated by the Natal lawyer and politician Harry Escombe, a 75 mm Troughton & Simms transit instrument, a clock by Dent keeping sidereal time, and some precision clocks and other minor instruments.Neison, E. Report of the superintendent, Natal Observatory, for 1883-4, p. FF159 A mean time clock by Victor Kullberg was added in 1892Neison, E. Report of the superintendent, Natal Observatory, for 1892-3, p. F1 and a 75 mm portable equatorial refractor in 1896.

Atmospheric super-rotation is the state where a planet's atmosphere rotates faster than the planet itself. The atmosphere of Venus is one example of extreme super-rotation; the Venusian atmosphere circles the planet in just four Earth days, much faster than Venus' sidereal day of 243 Earth days. Atmospheric super-rotation has also been observed on Titan, the largest moon of Saturn. It is believed that the Earth's thermosphere has a small net super- rotation in excess of the surface rotational velocity, although estimates of the size of the phenomenon vary widely.

Every Thursday inside the Church, demonstrations are held of the longest Foucault pendulum in Poland (46,5 m), suspended for the popular display of the Earth's rotation. Named after the French physicist Léon Foucault, the experimental apparatus consists of a tall pendulum free to swing in any vertical plane. The actual path of the swing appears to rotate; while in fact the plane is fixed in space, but the Earth rotates under the pendulum once a sidereal day. It is a simple and easy-to-see proof of the Earth's movement. Foucault’s Pendulum at ITOTD.

During the currency of ephemeris time as a standard, the details were revised a little. The unit was redefined in terms of the tropical year at 1900.0 instead of the sidereal year; and the standard second was defined first as 1/31556925.975 of the tropical year at 1900.0,ESAA 1992, p. 79: citing decision of International Committee for Weights and Measures (CIPM), Sept 1954. and then as the slightly modified fraction 1/31556925.9747 instead,ESAA (1992), see page 80, citing CIPM recommendation Oct 1956, adopted 1960 by the General Conference on Weights and Measures (CGPM).

33-42 Both deities served as the basis for the complex lunisolar Muisca calendar, having different divisions for synodic and sidereal months. The days were equal to the Gregorian calendar days and the three different years were composed of sets of different months; rural years of 12 or 13 months, common years of 20 months and holy years of 37 months.Duquesne, 1795Izquierdo Peña, 2014Izquierdo Peña, 2009 One of the most important religious figures in the Muisca religion was Bochica, the bearded messenger god. According to the myths, Bochica walked from Pasca to Iza.

Studying the asteroid with Rosetta space probe onboard OSIRIS cameras shortly before its flyby showed via a lightcurve analysis that Šteins has a rotation period of hours. The results of the rotational lightcurve agree with ground-based photometric observations of Šteins with a period of 6.049 hours and a brightness amplitude between 0.18 and 0.31 magnitude (). A lightcurve inversion also modeled a concurring sidereal period of 6.04681 hours and determined a spin axis at (250.0°, −89.0°) in ecliptic coordinates (λ, β). The modeling was done by compiling a set of 26 previously obtained visible lightcurves.

Additional observations by Christophe Demeautis in September 2017, and by Bruno Christmann in April 2020, gave a period of () and () hours with an amplitude of and magnitude, respectively (). In 2016, a modeled lightcurve rendered a concurring sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (83.0°, 40.0°) and (275.0°, 21.0°) in ecliptic coordinates (λ, β).

Mampalli copper plate (10th century AD) - earliest record to mention the Kollam Era. Malayalam Calendar or Kollam Era is a solar and sidereal Hindu calendar used in Kerala. The origin of the calendar has been dated as 825 CE. There are many theories regarding the origin of the era, but according to recent scholarship, it commemorated the foundation of Kollam after the liberation of the region (known as Venadu) from the Pandya rule by or with the assistance of the Chera king at Kodungallur.Noburu Karashmia (ed.), A Concise History of South India: Issues and Interpretations.

Later, he envisioned a clock that would show every conceivable type of time, from sidereal time to the rotation of the planets. Olsen's father was a weaver but apprenticed Olsen to a locksmith. However, he remained interested in clocks and read as much as he could about them and later astronomy. Even after ending his apprenticeship and becoming a locksmith Olsen continued to pursue these interests. In 1897, Olsen became a journeyman and eventually ended up in Strasbourg where he saw the famous clock built by Jean-Baptiste Schwilgué in the cathedral.

The Coriolis frequency ƒ, also called the Coriolis parameter or Coriolis coefficient, is equal to twice the rotation rate Ω of the Earth multiplied by the sine of the latitude φ. :f = 2 \Omega \sin \varphi.\, The rotation rate of the Earth (Ω = 7.2921 × 10−5 rad/s) can be calculated as 2π / T radians per second, where T is the rotation period of the Earth which is one sidereal day (23 h 56 min 4.1 s). In the midlatitudes, the typical value for f is about 10−4 rad/s.

As most countries and cultures of South and Southeast Asia lie within the Indian cultural sphere, the development of their traditional calendars have been strongly influenced by some form of the Hindu calendar. As in many other calendars, the New Year was based on the northern hemisphere vernal equinox (the beginning of spring). However, the Hindu calendar year was based on the sidereal year (i.e. the movement of the sun relative to the stars), while the Western Gregorian calendar is based on the tropical year (the cycle of seasons).

Science began to stagnate until ultimately knowledge became grounded in traditions handed down from generations long ago, the belief that the universe was ultimately understandable slowly faded, and a Time of Darkness descended over the planet. Much of Barker's writing concerns a time approximately 50,000 years after Tékumel has entered its pocket dimension.The 1509th century, according to Shawn Bond's A Chronological Presentation of Tekumel, the Sidereal Universe, and the Majesty of The Empire of The Petal Throne (1997). Five vast tradition- oriented civilizations occupy a large portion of the northern continent.

The ancient Book of Nut covers the subject of the decans. There were 36von Bomhard, Dr. A. S., The Egyptian Calendar: A Work for Eternity, London, 1999, page 51 decans (36 × 10 = 360 days), plus five added days to compose the 365 days of a solar based year. Decans measure sidereal time and the solar year is six hours longer; the Sothic and solar years in the Egyptian calendar realign every 1460 years. Decans represented on coffins from later dynasties (such as King Seti I) compared with earlier decan images demonstrate the Sothic-solar shift.

His nominal post at first was clerk and assistant to his brother, a tanner in St Helens, Merseyside, but for a period he was curator of the Liverpool Astronomical Institution and Observatory, where he also lectured. Henderson wrote in popular science journals, and continued his astronomical studies, becoming a member of thirteen scientific societies in England. On 9 September 1839 he married Betsy Coldstream Brody. In 1850 he was highly commended by George Biddell Airy, François Arago and others for a mechanism designed to show and check sidereal time.

When the geocentric ecliptic longitude of Venus coincides with that of the Sun, it is in conjunction with the Sun – inferior if Venus is nearer and superior if farther. The distance between Venus and Earth varies from about 42 million kilometres(at inferior conjunction) to about 258 million kilometres(at superior conjunction). The average period between successive conjunctions of one type is 584 days – one synodic period of Venus. Five synodic periods of Venus is almost exactly 13 sidereal Venus years and 8 Earth years, and consequently the longitudes and distances almost repeat.

Capricorn () is the tenth astrological sign in the zodiac out of twelve total zodiac signs, originating from the constellation of Capricornus, the horned goat. It spans the 270–300th degree of the zodiac, corresponding to celestial longitude. Under the tropical zodiac, the sun transits this area from about December 21 to January 21 the following year, and under the sidereal zodiac, the sun transits the constellation of Capricorn from approximately January 16 to February 16. In astrology, Capricorn is considered an earth sign, negative sign, and one of the four cardinal signs.

The guilty party had hidden the film in what he thought was a safe place because he subconsciously expected the night to last forever. Since the story was written, it has been discovered that Mercury is not tidally locked (a fact Asimov noted when the story appeared in subsequent anthologies printed after this advance in scientific knowledge). A Mercurian sidereal day is 58.6 Earth days long, while its solar day is as much as 176 days, due to a 3:2 spin resonance compared to its year at 88 days.

Civil Engineer Keith Hitchcock was appointed to look after the observatory building's renovation. In order to raise capital for the renovations some of the society's equipment was sold, including a vintage sidereal clock, which was a valuable antique. In addition to the renovation of the observatory's buildings, the Cooke telescope's mount was rebuilt by Terry Pearce, who, due to the observatories financial constraints, convivially accepted payment through instalments spread over a three-year period. Recent photo of the Hampstead Observatory Doug Daniels succeeded Henry Wildey as Astronomical secretary in 1988, following Wildey's retirement.

V. V. Sobolev not only made a fundamental contribution to each of the main partitions of that theory, but also was at the origins of five of those partitions. V. V. Sobolev lectured and headed the astrophysics sub department at Leningrad State University (Saint Petersburg State University). His monograph "Moving Sidereal Covers" (Leningrad State University publishing house, 113 pages) became the classics of theoretical astrophysics.Соболев В. В. Движущиеся оболочки звёзд Simultaneously V. V. Sobolev worked on a voluntary basis at the Astronomical observatory of Leningrad State University as director.

Most launch vehicles place geosynchronous satellites directly into a geosynchronous transfer orbit (GTO), an elliptical orbit with an apogee at GSO height and a low perigee. On-board satellite propulsion is then used to raise the perigee, circularise and reach GSO. Once in a viable geostationary orbit, spacecraft can change their longitudinal position by adjusting their semi-major axis such that the new period is shorter or longer than a sidereal day, in order to effect an apparent "drift" Eastward or Westward, respectively. Once at the desired longitude, the spacecraft's period is restored to geosynchronous.

Animation of Tundra orbit. inclination = 63.4° A Tundra orbit (Russian: Орбита «Тундра») is a highly elliptical geosynchronous orbit with a high inclination (approximately 63.4°), an orbital period of one sidereal day, and a typical eccentricity between 0.2 and 0.3. A satellite placed in this orbit spends most of its time over a chosen area of the Earth, a phenomenon known as apogee dwell, which makes them particularly well suited for communications satellites serving high latitude regions. The ground track of a satellite in a Tundra orbit is a closed figure 8 with a smaller loop over either the northern or southern hemisphere.

However, no follow-up observations have been published. , this asteroid is neither listed at Johnstons Archive nor has it any kind of binary status in the Lightcurve Data Base. In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (200.0°, −44.0°) and (38.0°, −50.0°) in ecliptic coordinates (λ, β).

In June 2011, a rotational lightcurve of Itha was obtained from photometric observations by Julian Oey at Kingsgrove Observatory , Australia, in collaboration with three Argentinian astronomers. Lightcurve analysis gave a well-defined rotation period of hours with a brightness variation of magnitude (). Two modeled lightcurves using photometric data from the Lowell Photometric Database and from the BlueEye600 robotic telescope at Ondřejov Observatory gave a sidereal period of and , respectively. The modelling of the former gave two poles at (59.0°, −59.0°) and (249.0°, −72.0°), while the one of the latter gave only one pole at (72.0°, −54.0°) in ecliptic coordinates (λ, β).

The Moon is an exceptionally large natural satellite relative to Earth: Its diameter is more than a quarter and its mass is 1/81 of Earth's. It is the largest moon in the Solar System relative to the size of its planet, though Charon is larger relative to the dwarf planet Pluto, at 1/9 Pluto's mass. The Earth and the Moon's barycentre, their common center of mass, is located (about a quarter of Earth's radius) beneath Earth's surface. The Earth revolves around the Earth-Moon barycentre once a sidereal month, with 1/81 the speed of the Moon, or about per second.

Modern discoveries about the true nature of celestial objects have undermined the theoretical basis for assigning meaning to astrological signs, and empirical scientific investigation has shown that predictions and recommendations based on these systems are not accurate. Astrology is generally regarded as pseudoscience. Various approaches to measuring and dividing the sky are currently used by differing systems of astrology, although the tradition of the Zodiac's names and symbols remain consistent. Western astrology measures from Equinox and Solstice points (points relating to equal, longest, and shortest days of the tropical year), while Jyotiṣa or Vedic astrology measures along the equatorial plane (sidereal year).

In February 2008, a rotational lightcurve of Datura was obtained from photometric observations by Naruhisa Takato using the Subaru telescope on Hawaii. Lightcurve analysis gave a sidereal rotation period of hours with a brightness amplitude of 0.46 magnitude (). The result is similar to observations by Wisniewski (3.2 h), Vokrouhlický (3.3583 h), and Székely (3.4 h). In 2013, lightcurve modelling by an international study using photometric data from the US Naval Observatory, the Uppsala Asteroid Photometric Catalogue and the Palmer Divide Observatory, gave a concurring rotation period of 3.358100 hours as well as a spin axis of (0°, 59.0°) in ecliptic coordinates (λ, β).

In September 2012, a first rotational lightcurve of Marconia was obtained from photometric observations by Robert Stephens at his Santana Observatory in California. Lightcurve analysis gave a well-defined rotation period of 19.16 hours with a brightness variation of 0.30 magnitude (). A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database, gave a concurring sidereal period of 19.2264 hours, as well as a spin axes of (37.0°, 31.0°) and (220.0°, 31.0°) in ecliptic coordinates (λ, β). Conversely, another lightcurve inversion study by an international collaboration gave a longer spin rate of 32.1201 hours.

The Celts used periods of darkness such as night and winter to begin their calculations of time. This meant that the first period of time in a "week" was a night, followed by a day. Further, they also counted the ending night period, giving rise to periods of time with more nights than days. In Irish, the term nómad is used to signify a small number of days and is exactly the length of the nine night week as in co cend nomaide - a period of time with nine nights divided nicely into a sidereal month of 27 nights.

It marks the end of the month with winter solstice for India and Nepal and the longest night of the year, a month that is called Pausha in the lunar calendar and Dhanu in the solar calendar in the Vikrami system. The festival celebrates the first month with consistently longer days. There are two different systems to calculate the Makara Sankranti date: nirayana (without adjusting for precession of equinoxes, sidereal) and sayana (with adjustment, tropical). The January 14 date is based on the nirayana system, while the sayana system typically computes to about December 23, per most Siddhanta texts for Hindu calendars.

Cosmic rays received on Earth exhibit daily variations in amplitude in solar time due to the distribution of cosmic rays in the inner heliosphere and to the Compton-Getting effect caused by Earth's orbital velocity around the Sun. Other daily variations in amplitude in sidereal time are caused by the anisotropy in the direction from which cosmic rays are received relative to the plane of our galaxy, the Milky Way. Both are contaminated by an annual seasonal variation. The daily solar variation is amplitude modulated by the seasonal variation of , producing sidebands on either side of the solar frequency, about , of and .

When describing orbits of binary stars, the orbital period is usually referred to as just the period. For example, Jupiter has a sidereal period of 11.86 years while the main binary star Alpha Centauri AB has a period of about 79.91 years. Another important orbital period definition can refer to the repeated cycles for celestial bodies as observed from the Earth's surface. An example is the so-called synodic period, applying to the elapsed time where planets return to the same kind of phenomena or location, such as when any planet returns between its consecutive observed conjunctions with or oppositions to the Sun.

The cost of such an orbit would be that an Earth-sized body would become tidally locked. When this happens, the object presents the same face to its parent at all times as it orbits, just as the Moon does with the Earth (more technically, one sidereal day is exactly equal to one year for the orbiting body). Traditional scientific theories proposed that such a tidally locked planet might be incapable of holding on to an atmosphere. Having such a slow rotation would weaken the magnetic effect that protects the atmosphere from being blown away by solar wind (see Rare Earth hypothesis).

In April 1983, a first rotational lightcurve of Sarema was obtained from photometric observations by American astronomer Richard Binzel. Lightcurve analysis gave a well-defined rotation period of 10.32 hours with a brightness amplitude of 0.81 magnitude (), which is indicative for an elongated, non- spherical shape. In 2009 and 2011, two modeled lightcurves gave a concurring sidereal period 10.30708 hours, combining sparse and dense photometric data from the Uppsala Asteroid Photometric Catalogue and other sources. The two studies also determined two spin axis of (45.0°, 67.0°) and (253.0°, 63.0°), as well as (51.0°, 64.0°) and (254.0°, 53.0°) in ecliptic coordinates (λ, β), respectively.

The Surya Siddhanta is a text on astronomy and time keeping, an idea that appears much earlier as the field of Jyotisha (Vedanga) of the Vedic period. The field of Jyotisha deals with ascertaining time, particularly forecasting auspicious day and time for Vedic rituals.James Lochtefeld (2002), "Jyotisha" in The Illustrated Encyclopedia of Hinduism, Vol. 1: A–M, Rosen Publishing, , pages 326–327 Max Muller, quoting passages by Garga and others for Vedic sacrifices, states that the ancient Vedic texts describe four measures of time – savana, solar, lunar and sidereal, as well as twenty seven constellations using Taras (stars).

Besides his career in economics, he performed experiments between 1952 and 1960 in the fields of gravitation, special relativity and electromagnetism, to investigate possible links between the fields. He reported three effects: # An unexpected anomalous effect in the angular velocity of the plane of oscillation of a paraconical pendulum, detected during two partial solar eclipses in 1954 and 1959. The claimed effect is now called the Allais effect. # Anomalous irregularities in the oscillation of the paraconical pendulum with respect to a sidereal diurnal periodicity of 23 hours 56 minutes and tidal periodicity of 24 hours 50 minutes.

A Molniya orbit (, "Lightning") is a type of satellite orbit designed to provide communications and remote sensing coverage over high latitudes. It is a highly elliptical orbit with an inclination of 63.4 degrees, an argument of perigee of 270 degrees, and an orbital period of approximately half a sidereal day. The name comes from the Molniya satellites, a series of Soviet/Russian civilian and military communications satellites which have used this type of orbit since the mid-1960s. The Molniya orbit has a long dwell time over the hemisphere of interest, while moving very quickly over the other.

The discovery of precession usually is attributed to Hipparchus (190–120 BC) of Rhodes or Nicaea, a Greek astronomer. According to Ptolemy's Almagest, Hipparchus measured the longitude of Spica and other bright stars. Comparing his measurements with data from his predecessors, Timocharis (320–260 BC) and Aristillus (~280 BC), he concluded that Spica had moved 2° relative to the autumnal equinox. He also compared the lengths of the tropical year (the time it takes the Sun to return to an equinox) and the sidereal year (the time it takes the Sun to return to a fixed star), and found a slight discrepancy.

The field of Jyotisha deals with ascertaining time, particularly forecasting auspicious day and time for Vedic rituals. The field of Vedanga structured time into Yuga which was a 5-year interval, divided into multiple lunisolar intervals such as 60 solar months, 61 savana months, 62 synodic months and 67 sidereal months. A Vedic Yuga had 1,860 tithis (, dates), and it defined a savana-day (civil day) from one sunrise to another. The Rigvedic version of Jyotisha may be a later insertion into the Veda, states David Pingree, possibly between 513 and 326 BCE, when Indus valley was occupied by the Achaemenid from Mesopotamia.

Using the geometric axis as the primary axis of a new body-fixed coordinate system, one arrives at the Euler equation of a gyroscope describing the apparent motion of the rotation axis about the geometric axis of the Earth. This is the so-called polar motion. Observations show that the figure axis exhibits an annual wobble forced by surface mass displacement via atmospheric and/or ocean dynamics, while the free nutation is much larger than the Euler period and of the order of 435 to 445 sidereal days. This observed free nutation is called Chandler wobble.

A solar day is complete. Solar time is measured by the apparent diurnal motion of the Sun, and local noon in apparent solar time is the moment when the Sun is exactly due south or north (depending on the observer's latitude and the season). A mean solar day (what we normally measure as a "day") is the average time between local solar noons ("average" since this varies slightly over the year). Earth makes one rotation around its axis in a sidereal day; during that time it moves a short distance (about 1°) along its orbit around the Sun.

The period of the Moon's orbit as defined with respect to the celestial sphere of apparently fixed stars (the International Celestial Reference Frame; ICRF) is known as a sidereal month because it is the time it takes the Moon to return to a similar position among the stars (): days (27 d 7 h 43 m 11.6 s). This type of month has been observed among cultures in the Middle East, India, and China in the following way: they divided the sky into 27 or 28 lunar mansions, one for each day of the month, identified by the prominent star(s) in them.

The Blue Plaque Soho House has been restored, retaining its 18th-century appearance, with "fine collections of ormolu, silver, furniture and paintings". Of particular note are the displays of silver and ormolu which were made in the manufactory, and the ormolu Sidereal clock made by Boulton and Fothergill, in 1771-72. There is a Blue Plaque commemorating Matthew Boulton on the house. The garden, once over 100 acres in size but now less than half an acre, contains a walk with sphinxes, dated to around 1795. Part of the garden has been recreated using Boulton’s original planting notes.

The astronomical basis of the Hindu lunar months. Also illustrates Adhika Masa (Year 2-Bhadrapada) repeats; the first time the Sun moves entirely within Simha Rashi thus rendering it an Adhika Masa Twelve Hindu mas (māsa, lunar month) are equal to approximately 354 days, while the length of a sidereal (solar) year is about 365 days. This creates a difference of about eleven days, which is offset every (29.53/10.63) = 2.71 years, or approximately every 32.5 months. Purushottam Maas or Adhik Maas is an extra month that is inserted to keep the lunar and solar calendars aligned.

It is 27.32158 days, very slightly shorter than the sidereal month (27.32166) days, because of precession of the equinoxes. # An anomalistic month is the average time the Moon takes to go from perigee to perigee—the point in the Moon's orbit when it is closest to Earth. An anomalistic month is about 27.55455 days on average. # The draconic month, draconitic month, or nodal month is the period in which the Moon returns to the same node of its orbit; the nodes are the two points where the Moon's orbit crosses the plane of the Earth's orbit.

In the horizontal coordinate system, the observer's meridian is divided into halves terminated by the horizon's north and south points. The observer's upper meridian passes through the zenith while the lower meridian passes through the nadir. Another way, the meridian is divided into the local meridian, the semicircle that contains the observer's zenith and both celestial poles, and the opposite semicircle, which contains the nadir and both poles. On any given (sidereal) day/night, a celestial object will appear to drift across, or transit, the observer's upper meridian as Earth rotates, since the meridian is fixed to the local horizon.

His value for the length of the sidereal year at 365 days 6 hours 12 minutes 30 seconds is only 3 minutes 20 seconds longer than the modern scientific value of 365 days 6 hours 9 minutes 10 seconds. A close approximation to π is given as: "Add four to one hundred, multiply by eight and then add sixty-two thousand. The result is approximately the circumference of a circle of diameter twenty thousand. By this rule the relation of the circumference to diameter is given." In other words, π ≈ 62832/20000 = 3.1416, correct to four rounded-off decimal places.

The annual path that the Sun appears to follow against the background of relatively fixed stars is known as the ecliptic. Since the Moon's orbit is inclined 5.14° to the ecliptic, the Moon will always remain within about 5° north or south of the ecliptic. For half of a sidereal month (with respect to the stars), the Moon is either north or south of the ecliptic. The two points where the Moon's orbit intersects that of Earth are called the lunar nodes; at the ascending node, the Moon moves north of the ecliptic, while at the descending node, the satellite moves south.

A Hardy clock showed sidereal time and a Brequet clock showed mean time. All instruments were mounted on solid masonry piers. There was also a Fortin pendulum and two instruments for observing the dip and variation of the magnetic needle. Some £470 was spent on the building in 1832, when the house was extended by two small rooms. In 1835, the transit was replaced by a 3½ foot (1.06m) Jones' transit circle, after which the mural circle was predominantly used because Dunlop believed the Jones circle was too difficult for one person to operate (Rosen 2003: pp. 86–87).

Modern ephemerides are often computed electronically, from mathematical models of the motion of astronomical objects and the Earth. However, printed ephemerides are still produced, as they are useful when computational devices are not available. The astronomical position calculated from an ephemeris is given in the spherical polar coordinate system of right ascension and declination. Some of the astronomical phenomena of interest to astronomers are eclipses, apparent retrograde motion/planetary stations, planetary es, sidereal time, positions for the mean and true nodes of the moon, the phases of the Moon, and the positions of minor celestial bodies such as Chiron.

The Brigadier became interested in astrology relatively early in life but it was not until after the war that he became really active in astrological circles. At first his interest extended to psychic studies and for many years he was president of the College of Psychic Studies in London. A big-framed man, known affectionately as "the Brig", Firebrace worked closely with the eminent siderealist Cyril Fagan (1896–1970) and gained a lifelong interest in sidereal astrology. Firebrace co-founded the Astrological Association of Great Britain with John Addey in 1958 and was its first president.

Navigational ephemeris tables record the geographic position of the First Point of Aries as the reference for position of navigational stars. Due to the slow precession of the equinoxes, the Zenith view (above a location) of constellations at a time of year from a given location have slowly moved west (by using solar epochs the drift is known). The tropical Zodiac is similarly affected and no longer corresponds with the constellations (the Cusp of Libra today is located within Virgo). In sidereal astrology, by contrast, the first point of Aries remains aligned with the Aries constellation.

Seen at the horizon, Phobos is about 0.14° wide; at zenith it is 0.20°, one-third as wide as the full Moon as seen from Earth. By comparison, the Sun has an apparent size of about 0.35° in the Martian sky. Phobos's phases, inasmuch as they can be observed from Mars, take 0.3191 days (Phobos's synodic period) to run their course, a mere 13 seconds longer than Phobos's sidereal period. As seen from Phobos, Mars would appear 6,400 times larger and 2,500 times brighter than the full Moon appears from Earth, taking up a quarter of the width of a celestial hemisphere.

Together with his brother, he helped Galileo win a lectureship in mathematics in Pisa in 1589 and in Padua in 1592. In the wake of Galileo’s discovery of the 'Medicean Planets', he gave the Cardinal a copy of his Sidereus Nuncius (Sidereal message) and a telescope as gifts (in 1610). When Galileo went to Rome in 1611, Grand Duke Cosimo II recommended him to the Cardinal’s council so that he could be helped during his sojourn at the Vatican.'Galileo, Courtier: The Practice of Science in the Culture of Absolutism', Mario Biagioli, University of Chicago Press, 1993.

In it he wrote on a great variety of subjects, including chess and whist. He was also the author of the articles on astronomy in the American Cyclopaedia and the ninth edition of the Encyclopædia Britannica, and was well known as a popular lecturer on astronomy in England, America and Australia. Proctor's map of Mars Elected a fellow of the Royal Astronomical Society in 1866, he became honorary secretary in 1872, and contributed eighty-three separate papers to its Monthly Notices. Of these the more noteworthy dealt with the distribution of stars, star clusters and nebulae, and the construction of the sidereal universe.

All three satellites broadcast directly to the consumer's receiver, but due to the highly elliptical orbit only two of them broadcast at any given time. Satellites Radiosat 1 through Radiosat 3, now decommissioned, fly in geosynchronous (not geostationary) Tundra orbits. Like the geostationary orbit, the tundra orbit has a period of 23 hours, 56 minutes (one sidereal day). Unlike the geostationary orbit, the tundra orbit is elliptical, not circular, and is inclined with respect to the equator rather than orbiting directly over it. The eccentric orbit ensures that each satellite spends about 16 hours of each day high over the continental United States.

The term Uttarāyaṇa (commonly Uttarayan) is derived from two different Sanskrit words "uttara" (North) and "ayana" (movement) thus indicating a semantic of the northward movement of the Earth on the celestial sphere. This movement begins to occur a day after the winter solstice in December which occurs around 22 December and continues for a six-month period through to the summer solstice around June 21 (dates vary ). This difference is because the solstices are continually precessing at a rate of 50 arcseconds / year due to the precession of the equinoxes, i.e. this difference is the difference between the sidereal and tropical zodiacs.

For the tropical zodiac used in Western astronomy and astrology, this means that the tropical sign of Aries currently lies somewhere within the constellation Pisces ("Age of Pisces"). The sidereal coordinate system takes into account the ayanamsa, ayan meaning transit or movement, and amsa meaning small part, i.e. movement of equinoxes in small parts. It is unclear when Indians became aware of the precession of the equinoxes, but Bhaskara 2's 12th-century treatise Siddhanta Shiromani gives equations for measurement of precession of equinoxes, and says his equations are based on some lost equations of Suryasiddhanta plus the equation of Munjaala.

Copernicus' version of trepidation combined the oscillation of the equinoxes (now known to be a spurious motion) with a change in the obliquity of the ecliptic (axial tilt), acknowledged today as an authentic motion of the Earth's axis. Trepidation was a feature of Hindu astronomy and was used to compute ayanamsha for converting sidereal to tropical longitudes. The third chapter of the Suryasiddhanta, verses 9-10, provides the method for computing it, which E. Burgess interprets as 27 degree trepidation in either direction over a full period of 7200 years, at an annual rate of 54 seconds.

Squire's proposals to determine longitude at sea drew on contemporary astronomy and other learned traditions, as well as heavily depending on her religious world view. Her books outlined a scheme that involved dividing the heavens into more than a million segments as well as a sidereal clock fixed to the position of the Star of Bethlehem at the birth of Jesus. Similarly religiously motivated searches were "not uncommon" at the time. The clock was intended to announce the time from church steeples, and she also discussed the use of marine buoys (described as artificial sea creatures) to aid mapping.

Ophiuchus (, ( "Serpent-bearer")) has sometimes been used in sidereal astrology as a thirteenth astrological sign in addition to the twelve signs of the tropical zodiac. The constellation Ophiuchus, as defined by the 1930 International Astronomical Union's constellation boundaries, is situated behind the sun from November 29 to December 18. The idea appears to have originated in 1970 with Stephen Schmidt's suggestion of a 14-sign zodiac, also including Cetus as a sign. A 13-sign zodiac has been promulgated by Walter Berg and by Mark Yazaki in 1995, a suggestion that achieved some popularity in Japan, where Ophiuchus is known as .

The sidereal year of 365.25636 days is only valid for stars on the ecliptic (the apparent path of the Sun across the sky), whereas Sirius's displacement ~40° below the ecliptic, its proper motion, and the wobbling of the celestial equator cause the period between its heliacal risings to be almost exactly 365.25 days long instead. This steady loss of one relative day every four years over the course of the 365-day calendar meant that the "wandering" day would return to its original place relative to the solar and Sothic year after precisely 1461 civil or 1460 Julian years.

In September 1992, a rotational lightcurve of Lalage was obtained from photometric observations by Polish astronomer Wiesław Wiśniewski. Lightcurve analysis gave a short rotation period of hours with a high brightness variation of magnitude, indicative of a non-spherical, elongated shape (). Since then, additional period determinations gave hours with an amplitude of magnitude () by David Higgins in October 2009, hours with an amplitude of magnitude () by Robert Stephens in January 2014, and hours with an amplitude of magnitude () by Daniel A. Klinglesmith in February 2014. A modeled lightcurves using photometric data from the BlueEye600 robotic telescope at Ondřejov Observatory gave a sidereal period of .

In October 2002, a rotational lightcurve of Adele was obtained from photometric observations by French amateur astronomer René Roy. Lightcurve analysis gave a well-defined rotation period of hours with a high brightness variation of magnitude, indicative of an elongated shape (). In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes at (301.0°, 44.0°) and (154.0°, 69.0°) in ecliptic coordinates (λ, β).

Lightcurve-based 3D-model of Erynia In January 2002, a rotational lightcurve of Erynia was obtained from photometric observations by French astronomer Laurent Bernasconi. Lightcurve analysis gave a rotation period of hours with a high brightness variation of magnitude, indicative of a non-spherical, elongated shape (). A concurring period of hours and an amplitude 0.47 magnitude was obtained by astronomers at the Palomar Transient Factory in April 2010 (). In 2011, a modeled lightcurve using data from the Uppsala Asteroid Photometric Catalogue (UAPC) and other sources gave a sidereal period hours, as well as two spin axes at (187.0°, −60.0°) and (335.0°, −74.0°) in ecliptic coordinates (λ, β).

In May 2004, a rotational lightcurve of Hildrun was obtained from photometric observations by Brian Warner at the Palmer Divide Observatory in Colorado. Lightcurve analysis gave a rotation period of hours with a brightness variation of magnitude (). Two tentative lightcurves were obtained by Pierre Antonini in June 2010, and by Robin Esseiva, Nicolas Esseiva and Raoul Behrend in April 2015; both with a period of hours and an amplitude of and magnitude, respectively (). In 2016, a modeled lightcurves using photometric data from various sources, rendered a concurring sidereal period of hours and two spin axes of (247.0°, −29.0°) and (86.0°, −63.0°) in ecliptic coordinates.

Since the middle of the first millennium BC the diurnal rotation of the fixed stars has been used to determine mean solar time, against which clocks were compared to determine their error rate. Babylonian astronomers knew of the equation of time and were correcting for it as well as the different rotation rate of the stars, sidereal time, to obtain a mean solar time much more accurate than their water clocks. This ideal mean solar time has been used ever since then to describe the motions of the planets, Moon, and Sun. Mechanical clocks did not achieve the accuracy of Earth's "star clock" until the beginning of the 20th century.

The astrarium made by the Italian astronomer and physician Giovanni Dondi dell'Orologio showed hour, year calendar, movement of the planets, Sun and Moon. Reconstruction, Museo nazionale della scienza e della tecnologia Leonardo da Vinci, Milan. The term is loosely used to refer to any clock that shows, in addition to the time of day, astronomical information. This could include the location of the sun and moon in the sky, the age and Lunar phases, the position of the sun on the ecliptic and the current zodiac sign, the sidereal time, and other astronomical data such as the moon's nodes (for indicating eclipses) or a rotating star map.

This arc is larger the farther north or south from the equator latitude, giving a more extreme difference between day and night and between seasons during the year. The Sun travels through the twelve signs of the zodiac on its annual journey, spending about a month in each. The Sun's position on a person's birthday therefore determines what is usually called his or her "sun" sign. However, the sun sign allotment varies between Western (sign change around 22-23 of every month) and Hindu astrology (sign change around 14-15 of every month) due to the different systems of planetary calculations, following the tropical and sidereal definitions respectively.

Column of protesters made several stops in front of the embassies of Romania, Germany, the United States and Russia. Participants at the unionist march voted for the formation of the National Unity Bloc (), adjoining 22 non-governmental entities, including: Civic Movement Youth of Moldova, Unionist Platform Action 2012, Association Light of Transnistrian Teachers, Queen Helen Foundation, Children Charity Foundation Sidereal Moment, Association of Former Deportees in USSR, Association Tiras-Bender, etc. The march ended with the signing of a Pact of Union, Pact for Europe. A bus with 50 members of the Moldovan Youth organization and others who wanted to attend the rally were blocked and legitimated by police in Cahul.

A number of dates are proposed by various astronomers and even wider timeframes by astrologers. (For an alternative approach to calibrating precession, see Alternative approach to calibrating precession in New, alternative, and fringe theories section below). As an example of a mystic contemporary approach to precession, in Max Heindel's astrology writings,A Rosicrucian Spiritual Astrology library, a Western Esoteric Christian astrology library it is described, that last time the starting-point of the sidereal zodiac agreed with the tropical zodiac occurred in AD 498. A year after these points were in exact agreement, the Sun crossed the equator about fifty seconds of space into the constellation Pisces.

The north and south celestial poles appear permanently directly overhead to observers at the Earth's North Pole and South Pole, respectively. As the Earth spins on its axis, the two celestial poles remain fixed in the sky, and all other points appear to rotate around them, completing one circuit per day (strictly, per sidereal day). The celestial poles are also the poles of the celestial equatorial coordinate system, meaning they have declinations of +90 degrees and −90 degrees (for the north and south celestial poles, respectively). Despite their apparently fixed positions, the celestial poles in the long term do not actually remain permanently fixed against the background of the stars.

The sidereal hour angle (SHA) of a body on the celestial sphere is its angular distance west of the vernal equinox generally measured in degrees. An alternate definition is that SHA of a celestial body is the arc of the Equinoctial or the angle at the celestial pole contained between the celestial meridian of the First point of Aries and that through the body, measured westward from Aries. The SHA of a star changes slowly, and the SHA of a planet doesn't change very quickly, so SHA is a convenient way to list their positions in an almanac. SHA is often used in celestial navigation and navigational astronomy.

The Lagna (Ascendant) is the exact point marked by the eastern horizon on the zodiac-belt that seemingly encircles the Earth; it is the point where the ecliptic cuts the horizon in the East. Hindu astrology, which is primarily based on constellations or nakshatras and on the equal house division, follows the Sidereal or the fixed zodiac. The entire sign or rasi rising in the east at the given local mean-time of birth or query is the first house or the Lagna. With the Rasi-chakra moving towards the East the count of signs or houses is from the eastern horizon, and their duration differs from latitude to latitude.

The Pale Blue Dot photo taken in 1990 by the Voyager 1 spacecraft showing Earth (center right) from nearly away, about 5.6 hours at light speed. Earth orbits the Sun at an average distance of about every 365.2564 mean solar days, or one sidereal year. This gives an apparent movement of the Sun eastward with respect to the stars at a rate of about 1°/day, which is one apparent Sun or Moon diameter every 12 hours. Due to this motion, on average it takes 24 hours—a solar day—for Earth to complete a full rotation about its axis so that the Sun returns to the meridian.

Gemini 4 would be the first multi-day space flight by the United States, designed to show that it was possible for humans to remain in space for extended lengths of time. The four-day, 66-orbit flight NASA reported that Gemini 4 made 62 revolutions, defined as passes over Cape Kennedy's longitude (), the duration of which is longer than an orbit because of the Earth's eastward rotation. This is analogous to the difference between a solar day and a sidereal day due to the Earth's revolution around the Sun. would approach but not break the five-day record set by the Soviet Vostok 5 in June 1963.

Balancing the increases of the common years against the losses of the leap years keeps the calendar date of the March equinox from drifting more than one day from 20 March each year. The March equinox may be taken to mark the beginning of astronomical spring and the end of astronomical winter in the Northern Hemisphere but marks the beginning of astronomical autumn and the end of astronomical summer in the Southern Hemisphere. In astronomy, the March equinox is the zero point of sidereal time and, consequently, right ascension. It also serves as a reference for calendars and celebrations in many human cultures and religions.

A geosynchronous orbit is an inclined orbit with an altitude of that completes one revolution every sidereal day tracing out a small figure-eight shape in the sky.Basics of the Geostationary Orbit By Dr. T.S. Kelso A geostationary orbit is a special case of geosynchronous orbit with no inclination, and therefore no apparent movement across the sky from a fixed observation point on the Earth's surface. Due to their inherent instability, geostationary orbits will eventually become inclined if they are not corrected using thrusters. At the end of the satellite's lifetime, when fuel approaches depletion, satellite operators may decide to omit these expensive manoeuvres to correct inclination and only control eccentricity.

The telescope is now in the Science Museum, London.See his book "Aedes Hartwellianae, or notices of the Mansion of Hartwell" (1851), which has illustrations by his wife, two of his sons, one daughter, and his son-in-law Baden Powell. He also produced observations in a publication on star colours entitled "Sidereal Chromatics" in 1864, which attempted to explain their nature, the effects of the Earth's atmosphere, and the possibility of change in colour due to Doppler Shift. While his premise proved ultimately wrong, he discussed and created a summary on observing star colours of many double stars under his so-called Hartwell Experiment.

This is a result of the Earth turning 1 additional rotation, relative to the celestial reference frame, as it orbits the Sun (so 366.25 rotations/y). The mean solar day in SI seconds is available from the IERS for the periods IERS Excess of the duration of the day to 86,400s … since 1623 Graph at end. and . Recently (1999–2010) the average annual length of the mean solar day in excess of has varied between and , which must be added to both the stellar and sidereal days given in mean solar time above to obtain their lengths in SI seconds (see Fluctuations in the length of day).

In 1847 the Astronomical Institution – having run out of money – handed the Royal Observatory over to the Government. Playfair Building and Playfair Monument in 1824 According to the English journalist William Jerdan, naturalist and oceanographer Edward Forbes, F.R.S. and his "The Red Lions", a dining club for younger members of the British Association, (named after the tavern where the first meeting was held), had occasion to run up to the observatory of Calton Hill for astronomical studies. The main purpose of the observatory was a time service. The transits of stars through the meridian were observed and used to keep the observatory clock, a sidereal clock manufactured by Robert Bryson, accurate.

Callippus started his observation cycle on the summer solstice, 330 BC, (28 June in the proleptic Julian calendar). The cycle's begin position, the stellar position and sidereal hour timing the eclipse, are used by later astronomers for calibrating their observations in relation to subsequent eclipses. The Callippic cycle of 76 years appears to be used in the Antikythera mechanism, an ancient astronomical mechanical clock and observational aide of the 2nd century BC (discovered in Mediterranean waters off Greece). The mechanism has a dial for the Callippic cycle and the 76 years are mentioned in the Greek text of the manual of this old device.

In September 2013, a rotational lightcurve of Manto was obtained from photometric observations by Frederick Pilcher at the Organ Mesa Observatory , New Mexico, in collaboration with Eduardo Manuel Alvarez, Andrea Ferrero, Daniel Klinglesmith and Julian Oey Lightcurve analysis gave an exceptionally long rotation period of hours with a notably high brightness amplitude of magnitude, indicative of an elongated shape (). With a period above 100 hours, the asteroid is a slow rotator. The result supersedes observations by Alain W. Harris from July 1981, and by astronomers at the Intermediate Palomar Transient Factory in California (). In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from a large collaboration of individual observers (such as above).

In October 1998, a rotational lightcurve of Thüringia was obtained from photometric observations by astronomers of the Minnesota State University Moorhead at Paul Feder Observatory. Analysis of the classically shaped bimodal lightcurve gave a well-defined rotation period of hours with a high brightness variation of magnitude, indicative of an irregular, non-spherical shape (). In October 2007, another period determination by Federico Manzini, Hiromi Hamanowa and Hiroko Hamanowa determined a period of hours and an amplitude of magnitude (). In 2011, a modeled lightcurve using data from the Uppsala Asteroid Photometric Catalogue (UAPC) and other sources gave a sidereal period 8.16534 hours, as well as a spin axis of (120.0°, −52.0°) in ecliptic coordinates (λ, β) ().

3D-model of Asplinda based on its lightcurve In December 2017, a rotational lightcurve of Asplinda was obtained from photometric observations by Brian Warner, Robert Stephens and Daniel Coley at the Center for Solar System Studies in California. Lightcurve analysis gave a rotation period of hours with a high brightness amplitude of magnitude, indicative of an elongated, non-spherical shape (). The results supersedes previous observations with a period determination of by the same astronomers in 2016, and a period of published by Mats Dahlgren in 1998 (). The 2017 observations by Warner, Stephens and Coley also gave two spin axes of (228.0°, 33.0°) and (46.0°, 45.0°) in ecliptic coordinates (λ, β) and a sidereal period of hours.

A lunisolar calendar is a calendar in many cultures whose date indicates both the Moon phase and the time of the solar year. If the solar year is defined as a tropical year, then a lunisolar calendar will give an indication of the season; if it is taken as a sidereal year, then the calendar will predict the constellation near which the full moon may occur. As with all calendars which divide the year into months there is an additional requirement that the year have a whole number of months. In this case ordinary years consist of twelve months but every second or third year is an embolismic year, which adds a thirteenth intercalary, embolismic, or leap month.

The main reason is that during the time that the Moon has completed an orbit around the Earth, the Earth (and Moon) have completed about of their orbit around the Sun: the Moon has to make up for this in order to come again into conjunction or opposition with the Sun. Secondly, the orbital nodes of the Moon precess westward in ecliptic longitude, completing a full circle in about 18.60 years, so a draconic month is shorter than a sidereal month. In all, the difference in period between synodic and draconic month is nearly days. Likewise, as seen from the Earth, the Sun passes both nodes as it moves along its ecliptic path.

The period for the Sun to return to a node is called the eclipse or draconic year: about 346.6201 d, which is about year shorter than a sidereal year because of the precession of the nodes. If a solar eclipse occurs at one new moon, which must be close to a node, then at the next full moon the Moon is already more than a day past its opposite node, and may or may not miss the Earth's shadow. By the next new moon it is even further ahead of the node, so it is less likely that there will be a solar eclipse somewhere on Earth. By the next month, there will certainly be no event.

The physical properties of this object were measured by an international team of astronomers led by Dr. Steven J. Ostro of the Jet Propulsion Laboratory using a radar telescope in California and optical telescopes in the Czech Republic, Hawaii, Arizona and California. ' is characterized as a potentially metallic X-type asteroid. Optical and radar observations indicate that it is a water- rich object. From light curve photometry in 1998, the object is measured to have a rotation period of only 10.7 minutes, which was considered to be one of the shortest sidereal days of any known Solar System object at the time; most asteroids with established rotational rates have periods measured in hours.

Since the edge of the plate represents the effective horizon, its centre identifies the pilot's nadir. Mounted behind the plate is a star-planisphere, based on a north pole stereographic zenithal projection (a projection from the north pole onto a plane passing through the south pole and perpendicular to the solar axis). This rotates once in a sidereal day on an axis passing through its south celestial pole and located some 13 cm above the centre of the horizon plate. For decoration it carries a few basic star patterns (considerably distorted owing to the projection used) and an eccentric zodiac/ecliptic/calendar ring faced with silver, and restricted in width to the distance between the solstitial points.

The second set, in addition to the north-south element, forms a complete circle and the sectors of two larger circles; all four wires intersect at the centre of the horizon plate (nadir) and a point near the top of the north-south line (zenith). The planisphere is attached to a large wheel driven by a worm gear, which is connected to a gear box containing the wheel- train. The gear wheels have ratios 45/29, 71/151, and 257/187, producing a solar to sidereal ratio of 821115 to 818873 ((45 x 71 x 257 ) to (29 x 151 x 187)). This produces a value for the mean tropical year of 365.24219447.

The worm gear serving the similar wheel of the mean-sun arm is connected to the input end of the gear box, and also, through a 3000:1 reduction gear, to a 1500 rpm synchronous electric motor running off the main electricity supply. For the equation correction, a wheel on a lever associated with the mean solar arm rolls round an annular cam of sheet brass about 61 cm in diameter. Beneath the planisphere, three small dials show hours, minutes, and seconds of Greenwich Mean Time, and three similar and balancing dials give local sidereal time in degrees, minutes, and seconds of arc. An aperture indicates the name of the day of the week.

It is moving closer to the Earth with a heliocentric radial velocity of −50 km/s, and is predicted to come as near as in around 3.3 million years. This is an aging giant star with a stellar classification of K5 III, having exhausted the supply of hydrogen at its core and expanded to 42 times the Sun's radius. It is radiating 391 times the luminosity of the Sun from its photosphere at an effective temperature of 3,972 K. 56 Aquilae is a double star, but it does not appear to be a binary star system. It is one of the double stars profiled in Admiral William Henry Smyth's 1864 work, Sidereal Chromatics.

Directly above the 24-hour dial is the dial of the Primum Mobile, so called because it reproduces the diurnal motion of the stars and the annual motion of the sun against the background of stars. It is basically an astrolabe drawn using a south polar projection, with a fixed tablet and a rete of special design that rotated once in a sidereal day. The rete was provided with 365 teeth, but was driven by a wheel with 61 teeth which made 6 turns in 24 hours. Thus the rete rotated once in 365/366 of a mean solar day, which equated 366 successive meridian transits of the vernal equinox with 365 similar transits of the sun.

Rutgers named the building after New York City businessman, Daniel S. Schanck, who donated a large portion of the funds to construct and equip the observatory. The cost of cost of construction and equipment amounted to US$6,166 (2013: US$86,845.07), of which US$2,400 (2013: US$33,802.82) was donated by Schanck (1812–1872). Rutgers equipped the observatory with "a 6.5-inch equatorial refracting telescope, a meridian circle with four-inch object glass for transit observations, a sidereal clock, a mean solar clock...chronograph, repeating circle, and other instruments." The Schanck Observatory served as the university's first astronomical facility and was used to provide instruction to its students through the nineteenth and early twentieth century.

Jansky finally determined that the "faint hiss" repeated on a cycle of 23 hours and 56 minutes. This period is the length of an astronomical sidereal day, the time it takes any "fixed" object located on the celestial sphere to come back to the same location in the sky. Thus Jansky suspected that the hiss originated outside of the Solar System, and by comparing his observations with optical astronomical maps, Jansky concluded that the radiation was coming from the Milky Way Galaxy and was strongest in the direction of the center of the galaxy, in the constellation of Sagittarius. An amateur radio operator, Grote Reber, was one of the pioneers of what became known as radio astronomy.

In February 2002, a rotational lightcurve of Klumpkea was obtained from seven consecutive nights of photometric observations by Robert Stephens at his Santana Observatory in California. Lightcurve analysis was difficult and only gave a provisional rotation period of hours with a high brightness amplitude of 0.77 magnitude (), indicative of an elongated shape. In 2016, a modeled lightcurve gave a concurring sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined a spin axis for Klumpkea of (172.0°, 48.0°) in ecliptic coordinates (λ, β).

The upper layer of troposphere exhibits a phenomenon of super-rotation, in which the atmosphere circles the planet in just four Earth days, much faster than the planet's sidereal day of 243 days. The winds supporting super-rotation blow at a speed of 100 m/s (≈360 km/h or 220 mph) or more. Winds move at up to 60 times the speed of the planet's rotation, while Earth's fastest winds are only 10% to 20% rotation speed. On the other hand, the wind speed becomes increasingly slower as the elevation from the surface decreases, with the breeze barely reaching the speed of 10 km/h (2.8 m/s) on the surface.

By now (the yellow grid) it has shifted (red arrow) to somewhere in the constellation of Pisces. Note that this is an astronomical description of the precessional movement and the vernal equinox position in a given constellation may not imply the astrological meaning of an Age carrying the same name, as they (ages and constellations) only have an exact alignment in the "first point of Aries", meaning once in each c. 25800 (Great Sidereal Year). The Earth, in addition to its diurnal (daily) rotation upon its axis and annual rotation around the Sun, incurs a precessional motion involving a slow periodic shift of the axis itself: approximately one degree every 72 years.

In November 2000, photometric observations by Brian Warner at the Palmer Divide Observatory () in Colorado Springs, Colorado, were used to build a lightcurve for Utopia. The asteroid displayed a rotation period of 13.61 hours and a brightness variation of 0.28 magnitude, revised from a previous publication that gave 13.60 hours and an amplitude of 0.29 (). In September 2005, French amateur astronomers Laurent Bernasconi, Raymond Poncy and Pierre Antonini obtained a lightcurve with a concurring period of 13.623 hours and an amplitude of 0.36 magnitude (). In 2011, a modeled lightcurve using data from the Uppsala Asteroid Photometric Catalogue (UAPC) and other sources gave a sidereal period 13.6228 hours, as well as a fragmentary spin axis of (n.a.

Because the Earth takes approximately 365.24 days to go around the Sun, the precise time of the equinox is not the same each year, and generally will occur about six hours later from one year to the next until reset by a leap year. February 29 of a leap year causes that year's vernal equinox to fall about eighteen hours earlier—according to the calendar—compared with the previous year. From 1800 to 2050 inclusive the vernal equinox date has (or will) range(d) from March 19 at 22:34 UT1 in 2048 to March 21 at 19:15 UT1 in 1903. Under the sidereal zodiac, the sun currently transits Aries from April 15 to 14 May (approximately).

Aryabhata asserted that the Moon, planets, and asterisms shine by reflected sunlight,Hayashi (2008), "Aryabhata I", Encyclopædia Britannica.Gola, 5; p. 64 in The Aryabhatiya of Aryabhata: An Ancient Indian Work on Mathematics and Astronomy, translated by Walter Eugene Clark (University of Chicago Press, 1930; reprinted by Kessinger Publishing, 2006). "Half of the spheres of the Earth, the planets, and the asterisms is darkened by their shadows, and half, being turned toward the Sun, is light (being small or large) according to their size." correctly explained the causes of eclipses of the Sun and the Moon, and calculated values for π and the length of the sidereal year that come very close to modern accepted values.

A star that is precisely at one of the ecliptic poles (at 90° from the ecliptic plane) will appear to move in a circle of radius \kappa about its true position, and stars at intermediate ecliptic latitudes will appear to move along a small ellipse. For illustration, consider a star at the northern ecliptic pole viewed by an observer at a point on the Arctic Circle. Such an observer will see the star transit at the zenith, once every day (strictly speaking sidereal day). At the time of the March equinox, Earth's orbit carries the observer in a southwards direction, and the star's apparent declination is therefore displaced to the south by an angle of \kappa.

This is similar to the seasonal behaviour of the Sun, but with a period of 27.2 days instead of 365 days. Note that a point on the Moon can actually be visible when it is about 34 arc minutes below the horizon, due to atmospheric refraction. Because of the inclination of the Moon's orbit with respect to the Earth's equator, the Moon is above the horizon at the North and South Pole for almost two weeks every month, even though the Sun is below the horizon for six months at a time. The period from moonrise to moonrise at the poles is a tropical month, about 27.3 days, quite close to the sidereal period.

The Meitei calendar or Manipuri calendar or Kangleipak calendar or Maliyapham Palcha Kumshing is a lunar and sidereal calendar used by the Meitei people of Manipur for their religious as well as agricultural activities. The concept of era known as Palcha kumching or Palsa era in meitei was first developed by Emperor Maliya Phampalcha, in the year 1397 BC in the kingdom of Kangleipak in present-day Manipur. It is believed that the 2nd , 3rd , 4th , the 6th and 7th months of the Meiteis calendar were named after Poireiten's Agricultural activities. Similar to Georgian calendar, the Meitei calendar also consists of twelve months and seven days but the starting date with the English calendar is different.

Lightcurve-based 3D-model of Tanina In February 2002, a rotational lightcurve of Tanina was obtained from photometric observations by Italian astronomer Andrea Ferrero at the Bigmuskie Observatory . Lightcurve analysis gave a well-defined rotation period of hours with a high brightness variation of magnitude, indicative of an elongated, non-spherical shape (). The result supersedes previous period determinations of hours with an amplitude of magnitude () by Wiesław Z. Wiśniewski from February 1992, and hours with an amplitude of magnitude () by Agnieszka Kryszczyńska in May 1999. In 2011, a modeled lightcurve using data from the Uppsala Asteroid Photometric Catalogue (UAPC) and other sources gave a sidereal period hours, as well as two spin axes at (46.0°, 48.0°) and (231.0°, 60.0°) in ecliptic coordinates (λ, β).

Given the date of an eclipse, one saros later a nearly identical eclipse can be predicted. During this 18-year period, about 40 other solar and lunar eclipses take place, but with a somewhat different geometry. One saros equaling 18.03 years is not equal to a perfect integer number of lunar orbits (Earth revolutions with respect to the fixed stars of 27.32166 days sidereal month), therefore, even though the relative geometry of the Earth–Sun–Moon system will be nearly identical after a saros, the Moon will be in a slightly different position with respect to the stars for each eclipse in a saros series. The axis of rotation of the Earth–Moon system exhibits a precession period of 18.59992 years.

Animation of Moon orbit around Earth from 2018 to 2027 Earth–Moon system (schematic) DSCOVR satellite sees the Moon passing in front of Earth The Moon makes a complete orbit around Earth with respect to the fixed stars about once every 27.3 days (its sidereal period). However, because Earth is moving in its orbit around the Sun at the same time, it takes slightly longer for the Moon to show the same phase to Earth, which is about 29.5 days (its synodic period). Unlike most satellites of other planets, the Moon orbits closer to the ecliptic plane than to the planet's equatorial plane. The Moon's orbit is subtly perturbed by the Sun and Earth in many small, complex and interacting ways.

In 2008, two rotational lightcurves of Odessa were obtained from photometric observations at the Hunters Hill and Oakley Southern Sky observatories in Australia. Lightcurve analysis gave a well-defined rotation period of 8.2426 and 8.244 hours with a brightness amplitude of 0.80 and 0.72 magnitude, respectively, indicative for a non- spherical shape (). In 2016, a modeled lightcurve gave a concurring sidereal period of 8.2444 hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys . The study also determined two spin axes of (25.0°, −81.0°) and (283.0°, −88.0°) in ecliptic coordinates (λ, β).

"The most accurate direction indicators for Pacific Islanders, still used in many parts of Oceania, are stars low in the sky that have either just risen or are about to set, that is horizon or guiding stars ... Although stars rise four minutes earlier each night ... the points on the horizon where they rise and set remain the same throughout the year." Thirty- two such stars were used to form a "sidereal compass" by which directions are given (first described by José Andía y Varela in 1774). Those in the east–west direction which rise in a nearly vertical direction are the easiest to use. Other stars with the same declination must be memorised in order to continue throughout the night.

The earlier study's §M found that Hipparchus did not adopt 26 June solstices until 146 BC when he founded the orbit of the Sun which Ptolemy later adopted. Dovetailing these data suggests Hipparchus extrapolated the 158 BC 26 June solstice from his 145 solstice 12 years later a procedure that would cause only minuscule error. The papyrus also confirmed that Hipparchus had used Callippic solar motion in 158 BC, a new finding in 1991 but not attested directly until P. Fouad 267 A. Another table on the papyrus is perhaps for sidereal motion and a third table is for Metonic tropical motion, using a previously unknown year of – days. This was presumably foundExplained at equation 25 of a recent investigation , paper #2.

The mass of this planet is exact since the inclination of the orbit is known, typical for transiting planets. This is a so-called “hot Jupiter” because this Jupiter-like gas giant planet orbits in a really close torch orbit around the star, making this planet extremely hot (in the order of a thousand kelvins). The distance from the star is roughly 20 times smaller than that of Earth from the Sun, which places the planet roughly 8 times closer to its star than Mercury is from the Sun. The “year” on this planet lasts only 3 days, 1 hour, 49 minutes, and 54 seconds, compared with Earth's 365 days, 6 hours, 9 minutes, and 10 seconds in a sidereal year.

The Rasmus Sørnes Clock. Arguably the most complicated of its kind ever constructed, the last of a total of four astronomical clocks designed and made by Norwegian Rasmus Sørnes (1893–1967), is characterized by its superior complexity compactly housed in a casing with the modest measurements of 0.70 x 0.60 x 2.10 m. Features include locations of the sun and moon in the zodiac, Julian calendar, Gregorian calendar, sidereal time, GMT, local time with daylight saving time and leap year, solar and lunar cycle corrections, eclipses, local sunset and sunrise, moon phase, tides, sunspot cycles and a planetarium including Pluto's 248-year orbit and the 25 800-year periods of the polar ecliptics (precession of the Earth's axis). All wheels are in brass and gold-plated.

For example, suppose that the Earth's orbital position is marked at the summer solstice, when the Earth's axial tilt is pointing directly toward the Sun. One full orbit later, when the Sun has returned to the same apparent position relative to the background stars, the Earth's axial tilt is not now directly toward the Sun: because of the effects of precession, it is a little way "beyond" this. In other words, the solstice occurred a little earlier in the orbit. Thus, the tropical year, measuring the cycle of seasons (for example, the time from solstice to solstice, or equinox to equinox), is about 20 minutes shorter than the sidereal year, which is measured by the Sun's apparent position relative to the stars.

This epoch causes the roughly 30 Indian calendar years to begin 23–28 days after the modern vernal equinox. The vernal equinox of the Surya Siddhanta librated 27° in both directions from the sidereal epoch. Thus the equinox moved 54° in one direction and then back 54° in the other direction. This cycle took 7200 years to complete at a rate of 54″/year. The equinox coincided with the epoch at the beginning of the Kaliyuga in −3101 and again 3600 years later in 499. The direction changed from prograde to retrograde midway between these years at −1301 when it reached its maximum deviation of 27°, and would have remained retrograde, the same direction as modern precession, for 3600 years until 2299.

In astrology, an astrological age has usually been defined by the constellation or superimposed sidereal zodiac in which the Sun actually appears at the vernal equinox. This is the method that Hipparchus appears to have applied around 127 BC when he calculated precession. Since each sign of the zodiac is composed of 30 degrees, each astrological age might be thought to last about 72 (years) × 30 (degrees) = about 2160 years. This means the Sun crosses the equator at the vernal equinox moving backwards against the fixed stars from one year to the next at the rate of one degree in seventy-two years, one constellation (on average) in about 2160 years, and the whole twelve signs in about 25,920 years, sometimes called a Platonic Year.

The polar orbit ranged between over Venus. The periapsis was located almost above the North pole (80° North latitude), and it took 24 hours for the spacecraft to travel around the planet. Venus Express studied the Venusian atmosphere and clouds in detail, the plasma environment and the surface characteristics of Venus from orbit. It also made global maps of the Venusian surface temperatures. Its nominal mission was originally planned to last for 500 Earth days (approximately two Venusian sidereal days), but the mission was extended five times: first on 28 February 2007 until early May 2009; then on 4 February 2009 until 31 December 2009; and then on 7 October 2009 until 31 December 2012. On 22 November 2010, the mission was extended to 2014.

At the start of the game, the player chooses an avatar, male or female. The evil Space Slug forces, led by the Sultan of Slime, have launched a sudden attack on humanity, quickly occupying the majority of planets in the galaxy, and forcing the Sidereal Shock Troops to recruit soldiers to counter the threat. After passing three "grueling tests", the player is made a "21-star general" and transported to the E.S.S. Dire Wolf, where they meet the ship's Flexible Interactive Digital Omnicomputer (FIDO, represented by a dog). From this point, the player receives various orders, from rescuing stranded agents on various cartoon-like worlds, retrieving upgrade parts for the ship and the player, and repairing various machines which help keep the universe running.

On the sides of the stela are carved two portraits of his father in a non-Maya style, dressed as a Teotihuacan warrior, bearing the central Mexican atlatl spear-thrower not adopted by the Maya, and carrying a shield adorned with the face of the Mexican god Tlaloc. The reverse of the stela bears a lengthy hieroglyphic inscription detailing the history of Tikal, including the Teotihuacan invasion that established Yax Nuun Ayiin I and his dynasty. In the Early Classic period the Maya kings began to dedicate a new stela, or other monument, to mark the end of each kʼatun cycle (representing 7,200 days, just under 20 sidereal years). At Tikal, the first to do so was king Kan Chitam who ruled in the late 5th century.

De Sitter offered a correction to be applied to the mean solar time given by the Earth's rotation to get uniform time. Other astronomers of the period also made suggestions for obtaining uniform time, including A Danjon (1929), who suggested in effect that observed positions of the Moon, Sun and planets, when compared with their well-established gravitational ephemerides, could better and more uniformly define and determine time.G M Clemence (1971). Thus the aim developed, to provide a new time scale for astronomical and scientific purposes, to avoid the unpredictable irregularities of the mean solar time scale, and to replace for these purposes Universal Time (UT) and any other time scale based on the rotation of the Earth around its axis, such as sidereal time.

The twenty-eight mansions of the Chinese astronomy The Twenty-Eight Mansions (), ', ' Gary D. Thompson chapter 11-24 or 'Richard Hinckley Allen in Star Names: Their Lore and Meaning are part of the Chinese constellations system. They can be considered as the equivalent to the zodiacal constellations in Western astronomy, though the Twenty-eight Mansions reflect the movement of the Moon through a sidereal month rather than the Sun in a tropical year. The lunar mansion system was in use in other parts of East Asia, such as ancient Japan; the Bansenshukai, written by Fujibayashi Yasutake, mentions the system several times and includes an image of the twenty-eight mansions. Another similar system, called Nakshatra, is used in traditional Indian astronomy.

Vishuddha Siddhanta Panjika provides articles on astrology and astronomy; annual predictions for the nation on subjects ranging from agriculture to politics; predictions on individual lagnas; and annual predictions on the basis of birth-stars. There are other regular sections like vedic months and dates from the Indian national calendar. Daily declination of the Sun, equation of time, sidereal time, planetary aspects, correct times of the eclipses, rising and setting times of the moon in different places, rising and setting times of the sun in Kolkata and seven other cities, monthly description of the night sky and locations of the stars and planets with explanatory sky maps are given. The dates of the main celebrations for the coming year are mentioned.

On one side of the codex the general format of each page largely follows the same arrangement, with a standing figure on the left hand side and a seated figure on the right hand side. Each page also contains the ajaw day glyph combined with a numerical coefficient, in each case representing a date marking the final day of a calendrical cycle. In spite of the poor state of preservation of the document, enough text has survived to demonstrate that in the case of the Paris Codex, the main series of dates correspond to kʼatun-endings, allowing for the reconstruction of some of the lost date glyphs in the text. The seated figures are each associated with a sidereal glyph indicating that they represent the ruling deity of each kʼatun.

Lightcurve-based 3D-model of Rotraut Two rotational lightcurves of Rotraut were obtained from photometric observations by Richard Ditteon at Oakley Southern Sky Observatory , Australia, in February 2017, and by Tom Polakis at the Command Module Observatory in Arizona in May 2018. Lightcurve analysis gave an identical rotation period of hours with a brightness variation of and magnitude, respectively (). The result supersedes a tentative period determination of hours and an amplitude of magnitude by French amateur astronomers Stéphane Charbonnel and Claudine Rinner from July 2002 (). In 2016, a modeled lightcurve gave a sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys .

He also published, in 1846, the first monthly magazine in the United States devoted specifically to astronomy, the Sidereal Messenger, and other works including The Orbs of Heaven (1848 and later), and Popular Astronomy (1860). When the American Civil War broke out, Mitchel turned soldier. He happened to be in New York when the news of the Battle of Fort Sumter came and, being asked to speak at a public meeting, poured out the deep emotions of his fervid soul in a passionate appeal whose eloquence produced an effect like that of the orations or Demosthenes, Cicero, and Burke. Men and women wept aloud; the cheering drowned his words and the speech he made has been regarded as worthy to be placed alongside abolitionists Abraham Lincoln, Charles Sumner, Wendell Phillips, and Henry Ward Beecher.

The hypothesis of aether drift implies that because one of the arms would inevitably turn into the direction of the wind at the same time that another arm was turning perpendicularly to the wind, an effect should be noticeable even over a period of minutes. The expectation was that the effect would be graphable as a sine wave with two peaks and two troughs per rotation of the device. This result could have been expected because during each full rotation, each arm would be parallel to the wind twice (facing into and away from the wind giving identical readings) and perpendicular to the wind twice. Additionally, due to the Earth's rotation, the wind would be expected to show periodic changes in direction and magnitude during the course of a sidereal day.

The optical system weighs and is manoeuvred on an alt-azimuth mount, with a total moving mass of (plus instruments). The BTA-6 and Multi Mirror Telescope had demonstrated during the 1970s the significant weight (and therefore cost) savings which could be achieved by the alt-azimuth design compared to the traditional equatorial mount for large telescopes. However, the alt-azimuth design requires continuous computer control, compensation for field rotation at each focus, and results in a 0.2 degree radius blind spot at zenith where the drive motors cannot keep up with sidereal motion (the drives have a maximum speed of one degree per second in each axis). The mount is so smooth and finely balanced that before the drive motors were installed it was possible to move the then assembly by hand.

The glories of the sky adverted to the Book of Job include a sidereal landscape vaguely described as "the chambers [i.e. penetralia] of the south". The phrase, according to Schiaparelli, refers to some assemblage of brilliant stars, rising 20 degrees at most above the southern horizon in Palestine about the year 750 B.C. (assumed as the date of the Patriarch Job), and, taking account of the changes due to precession, he points out the stellar pageant formed by the Ship, the Cross, and the Centaur meets the required conditions. Sirius, although at the date in question it culminated at an altitude of 41 degrees, may possibly have been thought of as belonging to the "chambers of the south"; otherwise, this splendid object would appear to be ignored in the Bible.

This longer period is called the anomalistic month and has an average length of days (27 d 13 h 18 m 33.2 s). The apparent diameter of the Moon varies with this period, so this type has some relevance for the prediction of eclipses (see Saros), whose extent, duration, and appearance (whether total or annular) depend on the exact apparent diameter of the Moon. The apparent diameter of the full moon varies with the full moon cycle, which is the beat period of the synodic and anomalistic month, as well as the period after which the apsides point to the Sun again. An anomalistic month is longer than a sidereal month because the perigee moves in the same direction as the Moon is orbiting the Earth, one revolution in nine years.

However, as one of the brighter stars close to the celestial pole, Polaris was used for navigation at least from late antiquity, and described as ἀεί φανής (aei phanēs) "always visible" by Stobaeus (5th century), and it could reasonably be described as stella polaris from about the High Middle Ages. In Shakespeare's play Julius Caesar, written around 1599, Caesar describes himself as being "as constant as the northern star", though in Caesar's time there was no constant northern star. Polaris was referenced in Nathaniel Bowditch's 1802 book, American Practical Navigator, where it is listed as one of the navigational stars. Twice in each sidereal day Polaris' azimuth is true north; the rest of the time it is displaced eastward or westward, and the bearing must be corrected using tables or a rule of thumb.

11 Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 hours long rather than the approximately 23-hour 56-minute sidereal day. Again, this is a simplification, based on a hypothetical Earth that orbits at uniform speed around the Sun.

There are two camps of thought among western astrologers about the "starting point", 0 degrees Aries, in the zodiac. Sidereal astrology uses a fixed starting point in the background of stars, while tropical astrology, used by the majority of Western astrologers, chooses as a starting point the position of the Sun against the background of stars at the Northern hemisphere vernal equinox (i.e. when the Sun position against the heavens crosses over from the southern hemisphere to the northern hemisphere) each year. As the Earth spins on its axis, it "wobbles" like a top, causing the vernal equinox to move gradually backwards against the star background, (a phenomenon known as the Precession of the equinoxes) at a rate of about 30 degrees (one Zodiacal sign length) every 2,160 years.

Veemente dio d’una razza d’acciaio, Automobile ebbra di spazio, che scalpiti e fremi d’angoscia rodendo il morso con striduli denti Formidabile mostro giapponese, dagli occhi di fucina, nutrito di fiamma e d’olî minerali, avido d’orizzonti, di prede siderali Io scateno il tuo cuore che tonfa diabolicamente, scateno i tuoi giganteschi pneumatici, per la danza che tu sai danzare via per le bianche strade di tutto il mondo! Vehement god from a race of steel, Automobile drunk with space, Trampling with anguish, bit between your strident teeth! O formidable Japanese monster with forge, Nourished with flame and mineral oils, Hungry for horizons and sidereal prey, I unleash your heart to the diabolical vroom-vroom And your giant radials, for the dance You lead on the white roads of the world.

All values of ΔT before 1955 depend on observations of the Moon, either via eclipses or occultations. The angular momentum lost by the Earth due to friction induced by the Moon's tidal effect is transferred to the Moon, increasing its angular momentum, which means that its moment arm (approximately its distance from the Earth, i.e. precisely the semi-major axis of the Moon's orbit) is increased (for the time being about +3.8 cm/year), which via Kepler's laws of planetary motion causes the Moon to revolve around the Earth at a slower rate. The cited values of ΔT assume that the lunar acceleration (actually a deceleration, that is a negative acceleration) due to this effect is = −26″/cy2, where is the mean sidereal angular motion of the Moon.

Lightcurve-based 3D-model of Amanda A rotational lightcurve of Amanda was obtained from photometric observations by European astronomers at the La Silla Observatory before 1995. Lightcurve analysis gave a well-defined rotation period of hours with a brightness variation of magnitude (). In October 2010, French amateur astronomer Maurice Audejean determined a concurring period of () hours with an amplitude of () magnitude (), while in August 2018, a further observation by the TESS-team reported a period of () hours and an amplitude of () magnitude (). In 2016, a modeled lightcurve gave a sidereal period of hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys .

The timepiece contains 920 individual parts, with 430 screws, 110 wheels, 120 removable parts, and 70 jewels, all of them handcrafted on a tiny scale. The timepiece is a gold, double-dialled and double-openfaced, minute repeating clockwatch with Westminster chimes, grande and petite sonnerie, split seconds chronograph, registers for 60-minutes and 12-hours, perpetual calendar accurate to the year 2100, moon-phases, equation of time, dual power reserve for striking and going trains, mean and sidereal time, central alarm, indications for times of sunrise/sunset and a celestial chart for the night time sky of New York City at 40 degrees 41.0 minutes North latitude. Its diameter is 74mm; thickness of case with glass 36mm; and weight of case 536g. The Supercomplication features the following 24 functions.

Also in the abbey, about the middle of the 11th century, William composed learned treatises on astronomy and music, disciplines that formed part of the quadrivium, in the knowledge of which William was considered unsurpassed in his day. He constructed various astronomical instruments, made a sun-dial which showed the variations of the heavenly bodies, the solstices, equinoxes and other sidereal phenomena."Bernoldi chronicon" in P. L., CXLVIII, 1404 His famous stone astrolabe can still be seen today in Regensburg: more than 2.5 metres high, it is engraved on the front with an astrolabe sphere, while on the reverse side is the figure of a man gazing into the heavens, presumed to be the Greek astronomer and poet Aratos of Soloi (of the 3rd century B.C.). He was also a skilled musician and made various improvements on the flute.

The year is usually represented by the 12 signs of the zodiac, arranged either as a concentric circle inside the 24-hour dial, or drawn onto a displaced smaller circle, which is a projection of the ecliptic, the path of the sun and planets through the sky, and the plane of the Earth's orbit. The ecliptic plane is projected onto the face of the clock, and, because of the Earth's tilted angle of rotation relative to its orbital plane, it is displaced from the center and appears to be distorted. The projection point for the stereographic projection is the North pole; on astrolabes the South pole is more common. The ecliptic dial makes one complete revolution in 23 hours 56 minutes (a sidereal day), and will therefore gradually get out of phase with the hour hand, drifting slowly further apart during the year.

Geography by Ptolemy, Latin manuscript of the early 15th century Ptolemy's second main work is his Geography (also called the Geographia), a compilation of geographical coordinates of the part of the world known to the Roman Empire during his time. He relied somewhat on the work of an earlier geographer, Marinos of Tyre, and on gazetteers of the Roman and ancient Persian Empire. He also acknowledged ancient astronomer Hipparchus for having provided the elevation of the north celestial poleThe north celestial pole is the point in the sky lying at the common centre of the circles which the stars appear to people in the northern hemisphere to trace out during the course of a sidereal day. for a few cities.Shcheglov D.A. (2002–2007): "Hipparchus’ Table of Climata and Ptolemy’s Geography", Orbis Terrarum 9 (2003–2007), 177–180.

An illustration of what Mars may have looked like during an ice age about 400,000 years ago caused by a large axial tilt As on Earth, the effect of precession causes the north and south celestial poles to move in a very large circle, but on Mars the cycle is 175,000 Earth years rather than 26,000 years as on Earth. As on Earth, there is a second form of precession: the point of perihelion in Mars's orbit changes slowly, causing the anomalistic year to differ from the sidereal year. However, on Mars, this cycle is 83,600 years rather than 112,000 years as on Earth. On both Earth and Mars, these two precessions are in opposite directions, and therefore add, to make the precession cycle between the tropical and anomalistic years 21,000 years on Earth and 56,600 years on Mars.

After Michell's death in 1793, Herschel bought a ten-foot-long, 30-inch reflecting telescope from Michell's estate. In 1797, Herschel measured many of the systems again, and discovered changes in their relative positions that could not be attributed to the parallax caused by the Earth's orbit. He waited until 1802 (in Catalogue of 500 new Nebulae, nebulous Stars, planetary Nebulae, and Clusters of Stars; with Remarks on the Construction of the Heavens) to announce the hypothesis that the two stars might be "binary sidereal systems" orbiting under mutual gravitational attraction, a hypothesis he confirmed in 1803 in his Account of the Changes that have happened, during the last Twenty- five Years, in the relative Situation of Double-stars; with an Investigation of the Cause to which they are owing. In all, Herschel discovered over 800 confirmedWilliam Herschel's Double Star Catalog. Handprint.

Clock drives work by rotating a telescope mount's polar axis, the axis parallel to the Earth's polar axis (also called the right ascension axis) in the opposite direction to the Earth's rotation one revolution every 23 hours and 56 minutes (called sidereal day), thereby canceling that motion.Turn left at Orion: a hundred night sky objects to see in a small telescope ... By Guy Consolmagno, Dan M. Davis, Karen Kotash Sepp, Anne Drogin, Mary Lynn Skirvin, page 204 This allows the telescope to stay fixed on a certain point in the sky without having to be constantly re-aimed due to the Earth's rotation. The mechanism itself used to be clockwork but nowadays is usually electrically driven. Clock drives can be light and portable for smaller telescopes or can be exceedingly heavy and complex for larger ones such as the 60-inch telescope at the Mount Wilson Observatory.

It contains the personal stories of five Air Aspected Dragon-Bloods, plus new charms, artifacts and signature characters. It also includes information on the Exalted signature character, Tepet Arada. (WW8840, August 2003, 1-58846-668-X) # Exalted: The Sidereals (by Bryan Armor, Rebecca Borgstrom, Geoff Grabowski, Steve Kenson, and John Snead): A sourcebook for Sidereal Exalted characters, including details on the Heavenly city of Yu-Shan. (WW8814, October 2003, 1-58846-669-8) # Kingdom of Halta (by Matthew McFarland and John Snead): This book details the Kingdom of Halta, magical beings of Halta, plus beasts, manses and sundry wonders. (WW8826, December 2003, 1-58846-670-1) # Exalted: The Outcaste (by White Wolf and White Wolf Publishing Inc): This book contains valuable information on those Dragon- Blooded who are not born to the scions of the Realm, but serve other powers or none at all.

It contains the personal stories of five Water Aspected Dragon-Bloods, plus new charms, artifacts and signature characters. It also includes information on the Exalted signature character, Peleps Deled. (WW8843, April 2005, 1-58846-679-5) # Cult of the Illuminated (by Daniel Dover, Mur Lafferty, and Patrick O'Duffy): This book details the workings of the Gold Faction Sidereal organization known as the Cult of the Illuminated, explaining the workings of the outer circle, the inner circle, the training camps and giving more details on the Wyld Hunt. (WW8829, May 2005, 1-58846-682-5) # Exalted: The Autochthonians (by Kraig Blackwelder, Michael Goodwin, John Snead, and Michael Kessler): A sourcebook detailing the parallel world of Autochthonia, and its artificially created champions, the Alchemical Exalted. (WW8816, May 2005, 1-58846-681-7) # Aspect Book: Wood (by George Holochwost, Ellen P. Kiley, and Exalted): A book outlining the Wood Aspected Terrestrial Exalted.

After Herschel discovered Titania and Oberon on January 11, 1787, he subsequently believed that he had observed four other moons: two on January 18 and February 9, 1790, and two more on February 28 and March 26, 1794. It was thus believed for many decades thereafter that Uranus had a system of six satellites, though the four latter moons were never confirmed by any other astronomer. Lassell's observations of 1851, in which he discovered Ariel and Umbriel, however, failed to support Herschel's observations; Ariel and Umbriel, which Herschel certainly ought to have seen if he had seen any satellites beside Titania and Oberon, did not correspond to any of Herschel's four additional satellites in orbital characteristics. Herschel's four spurious satellites were thought to have sidereal periods of 5.89 days (interior to Titania), 10.96 days (between Titania and Oberon), 38.08 days, and 107.69 days (exterior to Oberon).

A page from the Hindu calendar 1871-72 The Hindu calendar refers to a set of various lunisolar calendars that are traditionally used in the Indian subcontinent and South-east Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, however also differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start. Of the various regional calendars, the most studied and known Hindu calendars are the Shalivahana Shaka found in South India, Vikram Samvat (Bikrami) found in Nepal, North and Central regions of India, Tamil calendar used in Tamil Nadu – all of which emphasize the lunar cycle. Their new year starts in spring.

Similar increases in the size of the habitable zone were computed for other stellar systems. An earlier study by Ray Pierrehumbert and Eric Gaidos had eliminated the CO2-H2O concept entirely, arguing that young planets could accrete many tens to hundreds of bars of hydrogen from the protoplanetary disc, providing enough of a greenhouse effect to extend the solar system outer edge to 10 AU. In this case, though, the hydrogen is not continuously replenished by volcanism and is lost within millions to tens-of-millions of years. In the case of planets orbiting in the CHZs of red dwarf stars, the extremely close distances to the stars cause tidal locking, an important factor in habitability. For a tidally locked planet, the sidereal day is as long as the orbital period, causing one side to permanently face the host star and the other side to face away.

The importance of the tropical year for agriculture came to be realized much later than the adoption of lunar months for time keeping. However, it was recognized that the two cannot be easily coordinated over a short time span, so longer intervals were considered and the Metonic cycle was discovered as rather good, but not perfect, schema. The currently accepted values are: :235 synodic months (lunar phases) = 6,939.688 days (Metonic period by definition). :19 tropical years = 6,939.602 days The difference is 0.086 days for a cycle which mean that after a dozen returns there will be a full day of delay between the astronomical data and calculations. The error is actually one day every 219 years, or 12.4 parts per million. However, the Metonic cycle turned out to be very close to other periods: :254 sidereal months (lunar orbits) = 6,939.702 days :255 draconic months (lunar nodes) = 6,939.1161 days.

Suddenly, in the 1120th century (according to Shawn Bond)A Chronological Presentation of Tekumel, the Sidereal Universe, and the Majesty of The Empire of The Petal Throne (1997) and for reasons unknown, Tékumel and its star system (Tékumel's two moons, Gayél and Káshi, its sun, Tuléng, and four other planets, Ülétl, Riruchél, Shíchel, and Zirúna) were cast out of our reality into a "pocket dimension" (known as a béthorm in Tsolyáni), in which there were no other star systems. One hypothesis is that this isolation happened through hostile action on the part of an unknown party or group. Another is that the cosmic cataclysm was due to over-use of a faster than light drive which warped the fabric of space. No one knows, but the inhabitants of Tékumel, both human, native, and representatives of the other star-faring races, were now isolated and alone.

A lunar standstill is the gradually varying range between the northern and the southern limits of the Moon's declination, or the lunistices, over the course of one-half a sidereal month (about two weeks), or 13.66 days. (Declination is a celestial coordinate measured as the angle from the celestial equator, analogous to latitude.) One major, or one minor, lunar standstill occurs every 18.6 years due to the precessional cycle of the lunar nodes at that rate. At a major lunar standstill, the Moon's range of declination, and consequently its range of azimuth at moonrise and moonset, reaches a maximum. As a result, viewed from the middle latitudes, the Moon's altitude at upper culmination (the daily moment when the object appears to contact the observer's meridian) changes in just two weeks - from highest to lowest above the horizon due north or south, depending on the observer's hemisphere.

An object in such an orbit has an orbital period equal to the Earth's rotational period, one sidereal day, and so to ground observers it appears motionless, in a fixed position in the sky. The concept of a geostationary orbit was popularised by the science fiction writer Arthur C. Clarke in the 1940s as a way to revolutionise telecommunications, and the first satellite to be placed in this kind of orbit was launched in 1963. Communications satellites are often placed in a geostationary orbit so that Earth-based satellite antennas (located on Earth) do not have to rotate to track them but can be pointed permanently at the position in the sky where the satellites are located. Weather satellites are also placed in this orbit for real-time monitoring and data collection, and navigation satellites to provide a known calibration point and enhance GPS accuracy.

The modelled rotational period of the Moon pointer (averaged over a year) is 27.321 days, compared to the modern length of a lunar sidereal month of 27.321661 days. As mentioned, the pin/slot driving of the k1/k2 gears varies the displacement over a year's time, and the mounting of those two gears on the e3 gear supplies a precessional advancement to the ellipticity modelling with a period of 8.8826 years, compared with the current value of precession period of the moon of 8.85 years. The system also models the phases of the Moon. The Moon pointer holds a shaft along its length, on which is mounted a small gear named r, which meshes to the Sun pointer at B0 (the connection between B0 and the rest of B is not visible in the original mechanism, so whether b0 is the current date/mean Sun pointer or a hypothetical true Sun pointer is not known).

From an 1812 map, there existed in the Alto da Casa Branca in the Tapada of Ajuda an older observatory. The observatory was born from great controversy between French astronomer Hervé Faye (1814-1902), then director of the Observatory of Paris, and Peters, an astronomer at the Russian Observatory of Pulkova, on the parallax of the star of Argelander. The construction of the Lisbon observatory was due to a strong desire to build an institution that was a reference in Portuguese culture. It was established in the mid-19th century with the aim of promoting new Sidereal Astronomy, discovery and understanding of the infinite cosmos, and concern about the exact mapping of the sky and measuring the size of the universe. In 1850, Hervé Faye and Friedrich Georg Wilhelm von Struve (1793-1864) proposed that astronomical observations should be taken in Lisbon, being the first and "unique locale in all of continental Europe that the zenithal telescope could encounter the marvelous Argelander star".

JLC produces some complicated watches (Grand complication), e.g. the Master Gyrotourbillon 1Master Gyrotourbillon 1 (WatchAdvisor - YouTube) with a spherical Tourbillon. The Duomètre Sphérotourbillon is equipped with a tourbillon adjustable to the nearest second; the Reverso Répétition Minutes à Rideau is equipped with a minute- repeater shutter as a third face covering one of its two dials; the Master Grande Tradition Grande Complication is equipped with a flying tourbillon that follows the rhythm of celestial phenomena and indicates sidereal time, and a minute repeater comprising cathedral gongs; the Hybris Mechanica à Grande Sonnerie is equipped with gongs capable of playing the entire Big Ben chime; the Reverso Gyrotourbillon 2 is equipped with a spherical tourbillon principle, a reversible case and a cylindrical balance; the Master Compressor Extreme LAB is oil-free; the Gyrotourbillon 1 is equipped with a tourbillon evolving in three dimensions to compensate for the effects of gravity in all positions.

De Sitter and Clemence both referred to the proposal as 'Newtonian' or 'uniform' time. D Brouwer suggested the name 'ephemeris time'.ESAA (1992), see page 79. Following this, an astronomical conference held in Paris in 1950 recommended "that in all cases where the mean solar second is unsatisfactory as a unit of time by reason of its variability, the unit adopted should be the sidereal year at 1900.0, that the time reckoned in this unit be designated ephemeris time", and gave Clemence's formula (see Definition of ephemeris time (1952)) for translating mean solar time to ephemeris time. The International Astronomical Union approved this recommendation at its 1952 general assembly.At the IAU meeting in Rome 1952: see ESAE (1961) at sect.1C, p. 9; also Clemence (1971). Practical introduction took some time (see Use of ephemeris time in official almanacs and ephemerides); ephemeris time (ET) remained a standard until superseded in the 1970s by further time scales (see Revision).

Observations were made for the purpose of testing under field conditions the instruments and methods to be used in 1921. This expedition, to determine 129° east on the ground, created worldwide scientific interest and involved the cooperation of the Astronomer Royal and the Royal Observatory, Greenwich, with wireless time signals sent by the French wireless Service, that were transmitted from the Lyons astronomical observatory (Observatoire de Lyon) at Saint-Genis-Laval, near Lyons, France, between 17 and 24 November 1920. Wireless time signals were also sent from the Adelaide Observatory, transmitted by the Adelaide Radio Station, to enable the beats of the Adelaide sidereal clock to be used as a control on the rate of the chronometer used for the boundary observation. After these initial tests a comprehensive program was then arranged for the second stage of the border determinations, which were to take place during the following year and dates were then set for that to happen, from 20 April to 10 May 1921.

Poul Anderson, who had a degree in physics, worked out the physical framework for the anthology based on the characteristics of HD36395 as they were known in the early 1990s: one third of Earth Sun's mass, 82% of its diameter, spectral type M1 with a photosphere temperature of 3,400 K and a maximum emission in the near infrared. (The star is in fact very similar to Gliese 581, now known to have a planetary system.) The twin terrestrial planets are separated by an average distance of only 156,000 km (about 40% of the Earth-Moon distance). They orbit around their center of mass in 91 hours in locked rotation, which minimizes the effects of the huge tidal forces which they exert on each other. This constellation orbits Murasaki within the habitable zone, at a distance of only 0.223 astronomical units (sidereal year, 66 Earth days) where the planets receive about the same amount of total irradiation Mars gets from the Sun; however, with a spectral power distribution shifted to much longer wavelengths.

Clockwise, from top left: Copernicus, Gilbert, Kepler, Galileo Godwin's book appeared in a time of great interest in the Moon and astronomical phenomena, and of important developments in celestial observation, mathematics and mechanics. The influence particularly of Nicolaus Copernicus led to what was called the "new astronomy"; Copernicus is the only astronomer Godwin mentions by name, but the theories of Johannes Kepler and William Gilbert are also discernible. Galileo Galilei's 1610 publication Sidereus Nuncius (usually translated as "The Sidereal Messenger") had a great influence on Godwin's astronomical theories, although Godwin proposes (unlike Galileo) that the dark spots on the Moon are seas, one of many similarities between The Man in the Moone and Kepler's Somnium sive opus posthumum de astronomia lunaris of 1634 ("The Dream, or Posthumous Work on Lunar Astronomy"). Speculation on lunar habitation was nothing new in Western thought, but it intensified in England during the early 17th century: Philemon Holland's 1603 translation of Plutarch's Moralia introduced Greco-Roman speculation to the English vernacular, and poets including Edmund Spenser proposed that other worlds, including the Moon, could be inhabited.

The city of Kollam is a microcosm of Kerala state and its residents belong to varied religious, ethnic and linguistic groups.Menon, A Sreedhara; "A Survey of Kerala History"; DC Books, 1 January 2007 – History – pp 54–56 There are so many ancient temples, centuries-old churches and mosques in the city and its suburbs. ;Hindus and temples Kottarakkara Sree Mahaganapathi Kshethram Kollam is a Hindu majority city in Kerala. 56.35% of Kollam's total population belongs to Hindu community. Moreover, the Kollam Era (also known as Malayalam Era or Kollavarsham or Malayalam Calendar or Malabar Era), solar and sidereal Hindu calendar used in Kerala, has been originated on 825 CE (Pothu Varsham) at (Kollam) city. Anandavalleeshwaram Sri Mahadevar Temple is a 400 years old ancient Hindu temple in the city. The 400-year-old Sanctum sanctorum of this temple is finished in teak. Ammachiveedu Muhurthi temple is another major temple in the city that have been founded around 600 years ago by the Ammachi Veedu family, aristocrats from Kollam.

A member of the editorial board of Lights in the Night (Lumières dans la nuit) since 1969, he wrote numerous articles on UFOs, mysticism, the animal kingdom as well as other topics in various journals.(Arts, Science et Vie, Tout Savoir, Monde et Vie, Encyclopédie Larousse « Découvrir les Animaux » in 1971, Planète - apologist for Réalisme fantastique including other participants Remy Chauvin, Bernard Heuvelmans, Charles Noël Martin, Jean E. Charon and George Langelaan -, Phénomènes Spatiaux, Recherches ufologiques, Question de, France Catholique, Ecclésia, Flying Saucer Review, Archeologia (with an article on his village where he was born), etc.) In the journal The Life of the Animals (La vie des bêtes), during the 1960s, he authored the column The Mysteries of the Animal Kingdom (Les mystères du monde animal). From September 26 to October 10, 1964, Aimé Michel also led cultural workshops on the theme of "Life in the Sidereal Universe" (La vie dans l'Univers sidéral), taking place under the auspices of the magazine Planet (Planète) at Cefalu in Sicily. He wrote the television screenplay Mycènes Celui qui vient du futur: Mycènes, He who comes from the future.

Moreover, he is recognized as the first Spanish in calculating the orbit of a double star system in the country, the STT 77. It follows the appointment of Aller as a member of the “International Astronomical Union Commission 26 (double stars)” in 1948 (Zurich). The following year he was named a member of the National Commission on Astronomy. The professor Aller Ulloa also designed and built devices for measuring and observation purchased by the Paris Observatory; he suggested modifications on the production of the astrograph to the German manufacture Zeiss, which accepted them and afterwards did not accept the payment of Aller Ulloa for the device as appreciation for the improvements; a clock of sidereal time; a base for the portable vertical circle monocular, etc..."Ramón María Aller Ulloa" Contistuted by his two main research lines double stars and the methods to determine coordinates based on two vertical lanes he published 78 articles in especialized publications in Europe, 4 books and he directed 5 PhD thesis (Between 1960 and 1963, in spite of being 83 years old, Aller still directed three theses: Múgica Buhigas's “ber die Anwendung des Theodolits in der Geodtischen Astronomia” (Munich, 1960); Zaera de Toledo's “On determining the Orbits of Visual Double Stars.