411 Sentences With "ephemeris" | Random Sentence Generator

The Photographer's Ephemeris helps you figure out the perfect lighting.

Meanwhile, there was increasing systematization in the production of ephemeris tables.

The result of all this was the JPL Development Ephemeris (JPL DE).

That's because an ephemeris doesn't spell out the planets' positions for you.

Equivalenze showcases new sculptures from Penone, as well as a short film, Ephemeris.

Like we said, though, it's pretty hard to understand an ephemeris if you haven't studied astrology.

But the issue is that UTC has a complicated relationship to the time used in the astronomical ephemeris.

More accurately, astrologers are generally working from a laptop, poring over a table of planetary positions known as an ephemeris.

Thankfully, you don't have to be bona fide astrologer who carries around an ephemeris to know when the next full moon is coming.

For our example, this is what all the inputs should look like: Click "Generate Ephemeris" and a whole bunch of data should pop up.

Well, for every thousand years covered, the ephemeris has about 22744 megabytes of results, given as coefficients for Chebyshev polynomials, which are convenient for interpolation.

And what a modern ephemeris does is to quote the results for positions of bodies in the solar system relative to the times on those clocks.

Stretch your imagination The app's name is weird, and the app itself is even weirder – but if you're really into photography, Ephemeris is a very powerful tool.

You may think that this sounds like some sort of cheat sheet, but that's probably because you haven't spent much time trying to read an ephemeris yourself.

If you want to take your Mercury retrograde preparation to a more advanced level, you can look at an ephemeris, a list of all the dates and the planetary positions.

Tripp says you can find out about transits ahead of time by looking up an ephemeris, or a table listing all of the planets' movements in the upcoming months and years.

He had never shot a rocket before, but used The Photographer's Ephemeris, a map-centric sun and moon calculator, as well as Google Maps to figure out where to set up his shots.

Tali Edut, one half of the Astrotwins, tells us one of the most important tools in an astrologer's arsenal is an ephemeris, or a table of the heavenly bodies' positions in a given year.

According to astrologer Annie Heese's ephemeris (aka her table of future planetary activity), summer 2018 will see seven planetary retrogrades in total, although the most planets that will be retrograde at one time is six.

Even if your astrologer prefers to use a software program to pull up the exact movements of a specific planet, learning to read an ephemeris — and using it regularly — was absolutely part of their training.

And back in Babylonian times the idea arose of using these to construct an ephemeris—a systematic table that said where a particular heavenly body such as the Moon was expected to be at any particular time.

Ephemeris: The Questrison Saga: Book Two by J. Dianne Dotson In the latest installment of her Questrison saga, J. Dianne Dotson follows the story of Galla-Deia, a humanoid creature who was discovered in space and raised in a city of androids.

You can keep track of Venus' general movements by looking at an ephemeris (a day-by-day table of all planetary activity), but for those of you who want to know precisely when your Venus return will occur, there are a few sites that help you calculate those dates.

Instead, it lists their placement by degrees on the Wheel of the Zodiac so that astrologers can see where a planet is in relation to each of the 12 signs, plus where it's headed next (you have an ephemeris to thank for any long-term predictions you read in your horoscope).

" He added: "By day I was covering toxic tort litigation, and at night I would hang out in my girlfriend's room in Woodstock and pore through the ephemeris and the New York Post horoscope with a red pencil and tarot deck, and I hacked the Patric Walker horoscope, like Julian Assange.

It is the largest of the ephemerides files at 3.4 gigabytes. This ephemeris file is used by the JPL Horizons On- Line Ephemeris System.

Beginning in 1981, the title The American Ephemeris and Nautical Almanac and the British title The Astronomical Ephemeris were completely merged under the single title The Astronomical Almanac.

Ephemeris time based on the standard adopted in 1952 was introduced into the Astronomical Ephemeris (UK) and the American Ephemeris and Nautical Almanac, replacing UT in the main ephemerides in the issues for 1960 and after.ESAA 1992, at p.612. (But the ephemerides in the Nautical Almanac, by then a separate publication for the use of navigators, continued to be expressed in terms of UT.) The ephemerides continued on this basis through 1983 (with some changes due to adoption of improved values of astronomical constants), after which, for 1984 onwards, they adopted the JPL ephemerides. Previous to the 1960 change, the 'Improved Lunar Ephemeris' had already been made available in terms of ephemeris time for the years 1952-1959"Improved Lunar Ephemeris", US Government Printing Office, 1954.

Raphael's Ephemeris is a set of tables used by astrologers which lists the zodiacal positions of astronomical bodies: the Sun, Moon and planets. More recently, the ephemeris includes some asteroids and the ‘centaur’ planet known as 2060 Chiron. Raphael’s Ephemeris, the oldest of its kind, is published annually in a portable booklet and in large multi-year volumes.

P. Kenneth Seidelmann (ed.), Explanatory Supplement to the Astronomical Almanac: A Revision to the Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac (Sausalito [CA]: University Science Books, 1992).

The ephemeris time of the 1952 standard leaves a continuing legacy, through its ephemeris second which became closely duplicated in the length of the current standard SI second (see below: Redefinition of the second).

The Astronomical Almanac is the direct descendant of the British and American navigational almanacs. The British Nautical Almanac and Astronomical Ephemeris had been published since 1766, and was renamed The Astronomical Ephemeris in 1960. The American Ephemeris and Nautical Almanac had been published since 1852. In 1981 the British and American publications were combined under the title The Astronomical Almanac.

This ephemeris was utilized in the Astronomical Almanac from 2003 until 2014. DE406 was released with DE405 in 1998. A Long Ephemeris, this was the condensed version of DE405, covering 3000 BC to AD 3000 with the same limitations as DE404.

Although this is an independent definition that does not refer to the older basis of ephemeris time, it uses the same quantity as the value of the ephemeris second measured by the cesium clock in 1958. This SI second referred to atomic time was later verified by Markowitz (1988) to be in agreement, within 1 part in 1010, with the second of ephemeris time as determined from lunar observations. For practical purposes the length of the ephemeris second can be taken as equal to the length of the second of Barycentric Dynamical Time (TDB) or Terrestrial Time (TT) or its predecessor TDT.

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).

The updated orbital data were then used in another phase of the same computer program to yield the geocentric ephemeris. From the geocentric ephemeris, three different products were computed and sent back to the observing stations for their planning of future observing opportunities.

There have been many versions of the JPL DE, from the 1960s through the present,See, for example, ; ; ; see also Newhall, Standish and Williams (1983). in support of both robotic and manned spacecraft missions. Available documentation is sketchy, but we know DE69 was announced in 1969 to be the third release of the JPL Ephemeris Tapes, and was a special purpose, short-duration ephemeris. The then-current JPL Export Ephemeris was DE19.

It is also necessary to have a relatively good ephemeris of the target before observing it.

The ephemeris is generally valid for 4 hours, with provisions for updates every 4 hours or longer in non-nominal conditions. The time needed to acquire the ephemeris is becoming a significant element of the delay to first position fix, because as the receiver hardware becomes more capable, the time to lock onto the satellite signals shrinks; however, the ephemeris data requires 18 to 36 seconds before it is received, due to the low data transmission rate.

This confirmed the unsuitability of the mean solar second of Universal Time as a precision measure of time interval. After three years of comparisons with lunar observations it was determined that the ephemeris second corresponded to 9,192,631,770 ± 20 cycles of the caesium resonance. In 1967/68 the length of the SI second was redefined to be 9,192,631,770 cycles of the caesium resonance, equal to the previous measurement result for the ephemeris second (see Ephemeris time - redefinition of the second).

Data for Pluto was added in 1950.P. Kenneth Seidelmann, ed., Explanatory Supplement to the Astronomical Almanac (Mill Valley, California: University Science Books, 1992) 613–615. Beginning in 1960, all parts except for a few introductory pages were jointly calculated and typeset by the American Nautical Almanac Office and Her Majesty's Nautical Almanac Office but published separately within The American Ephemeris and Nautical Almanac and The Astronomical Ephemeris, a new name for the old British title The Nautical Almanac and Astronomical Ephemeris.

Ephemeris time was a first application of the concept of a dynamical time scale, in which the time and time scale are defined implicitly, inferred from the observed position of an astronomical object via the dynamical theory of its motion.B Guinot and P K Seidelmann (1988), at p.304-5. # a modern relativistic coordinate time scale, implemented by the JPL ephemeris time argument Teph, in a series of numerically integrated Development Ephemerides. Among them is the DE405 ephemeris in widespread current use.

XEphem is a Motif based ephemeris and planetarium program for Unix-like operating systems developed by Elwood C. Downey.

The ephemeris is a table of the calculated positions of astronomical objects and various other data, usually for a specific time of the day, either noon or midnight. A uniform time measurement is needed to establish accuracy, and ephemerides will use variously Greenwich Mean Time, Universal Time or Ephemeris Time. Historically, the ephemeris was used for astrology and dates back to ancient Babylon. However, ephemerides became highly useful to navigators and astronomers, and were officially recognised by governments from about the early modern period.

The American Ephemeris and Nautical Almanac was published for the years 1855 to 1980, containing information necessary for astronomers, surveyors, and navigators. It was based on the original British publication, The Nautical Almanac and Astronomical Ephemeris, with which it merged to form The Astronomical Almanac, published from the year 1981 to the present.

Omoglymmius ephemeris is a species of beetle in the subfamily Rhysodidae. It was described by R.T. & J.R. Bell in 1982.

The radio frequency is 124.980 "Pavullo Radio" and the airport is open to traffic every day with local time 08:00 until the ephemeris for fixed-wing aircraft; it is open to traffic every day H24 for rotary wing aircraft. Beyond the time of the ephemeris for the operations a 30 minutes notice is required.

Dunthorne also contributed a method for clearing nautical lunar observations of the effects of refraction and parallax, for the purpose of finding the longitude at sea, and Maskelyne included this in his 'Tables requisite to be used with the Nautical Ephemeris','Tables requisite to be used with the Nautical Ephemeris' (2nd edition, 1781). an accessory volume published to accompany the Nautical Almanac.Maskelyne's acknowledgement of Dunthorne is included in early editions, e.g. the Nautical Almanac and Astronomical Ephemeris for the year 1768, especially at the preface (unnumbered second page).

"The MARYLAND, Virginia and Pennsylvania Almanack and Ephemeris for 1780. By David Rittenhouse. Baltimore: M. K. Goddard." (5) Morrison, p. 132.

Gr. N. Bobrinskaya. Planet Ephemeris (147) Protogeneia. Proceedings of the Imperial Academy of Sciences. Series V. T.7, No. 1, June 1897.

To make progress in automating ephemeris forecasts, Aeronutronic and TRW Inc. developed sophisticated new programs. Squadron orbital analysts evaluated the two programs.

Terrestrial Time is a theoretical uniform time scale, defined to provide continuity with the former Ephemeris Time (ET). ET was an independent time- variable, proposed (and its adoption agreed) in the period 1948–52Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac, Nautical Almanac Offices of UK and US (1961), at pp. 9 and 71. with the intent of forming a gravitationally uniform time scale as far as was feasible at that time, and depending for its definition on Simon Newcomb's Tables of the Sun (1895), interpreted in a new way to accommodate certain observed discrepancies.

In 1690 Parker began publishing of an almanac, Mercurius Anglicanus; or the English Mercury, London, which continued under his name until 1781. In 1703 it was called A Double Ephemeris, and in 1707 Parker's Ephemeris. The number for 1720 was entitled Parker's Mercurius Anglicanus, but the title of Parker's Ephemeris resumed the following year. Having included in one of his almanacs the Chevalier de St. George, in other words the Old Pretender, among the sovereigns of Europe, he was fined and forbidden to publish any more almanacs; he printed for some time a bare calendar, with the saints' days only.

1977, DE111 in May 1980, DE118 in Sep. 1981, and DE200 in 1982. DE102 was the first numerically integrated so-called Long Ephemeris, covering much of history for which useful astronomical observations were available: 1141 BC to AD 3001. DE200, a version of DE118 migrated to the J2000.0 reference frame, was adopted as the fundamental ephemeris for the new almanacs starting in 1984.

Venus,"Tables of the Heliocentric Motion of Venus", in: Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac, volume VI (1898), pp. 271-382 [Part III]. Mars,"Tables of the Heliocentric Motion of Mars", in: Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac, volume VI (1898), pp. 383-586 [Part IV].

Uranus"Tables of the Heliocentric Motion of Uranus", in: Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac, volume VII (1898), pp. 287-416 [Part III]. and Neptune;"Tables of the Heliocentric Motion of Neptune", in: Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac, volume VII (1898), pp. 417-471 [Part IV].

The term ephemeris time (often abbreviated ET) can in principle refer to time in connection with any astronomical ephemeris. In practice it has been used more specifically to refer to: # a former standard astronomical time scale adopted in 1952 by the IAU,'ESAE 1961': 'Explanatory Supplement (1961), esp. p.9. and superseded in the 1970s.'ESAA (1992)': P K Seidelmann (ed).

Setting circles in conjunction with a star chart or ephemeris allow the telescope to be easily pointed at known objects on the celestial sphere.

The first national astronomical ephemeris, Connaissance de Temps, was published in France in 1679. In 1767 came the Nautical Almanac and Astronomical Ephemeris, which is issued annually by the Royal Observatory at Greenwich.The Columbia Electronic Encyclopaedia, (Sixth Edition), Columbia University Press, 2011. There are different types of ephemerides, and a distinction needs to be made between those used for astronomy and those for astrology.

It covers its history, significance, sources, methods of computation, and use of the data. Because the Astronomical Almanac prints primarily positional data, this book goes into great detail on techniques to get astronomical positions. Earlier editions of the supplement were published in 1961Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac (London: Her Majesty's Stationery Office, 1961). and in 1992.

At present she is head of the Laboratory of Ephemeris Astronomy of this institute. Major research interests of Dr. Pitjeva include the construction of numerical ephemerides of the planets, the determination of the planets' and asteroids' masses, the parameters of planet rotation and planetary topography, the solar corona and oblateness and general relativity testing. She is one of creators of the numerical Ephemerides of Planets and the Moon (EPM) of IAA RAS that originated in the seventies of the past century and have been developed since that time. The version of the EPM2004 ephemeris has been adopted as the ephemeris basis of Russian Astronomical Yearbook since 2006.

The Nautical Almanac has been the familiar name for a series of official British almanacs published under various titles since the first issue of The Nautical Almanac and Astronomical Ephemeris, for 1767: this was the first nautical almanac to contain data dedicated to the convenient determination of longitude at sea. It was originally published from the Royal Greenwich Observatory in England. 'ESAE 1961': Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac ('prepared jointly by the Nautical Almanac Offices of the United Kingdom and the United States of America', HMSO, London, 1961)'ESAA 1992': ed. P.K. Seidelmann, Explanatory Supplement to the Astronomical Almanac (CA, 1992).

Cross was originally named Frederick Robert Cross, but dropped the "Frederick". He began studying astrology quite young and by the age of twenty-five, already married with two sons, he was teaching astrology and accepting clients, and soon became the editor of The Prophetic Messenger, which he renamed to Raphael's Ephemeris. In the 1870s he obtained the copyright to Raphael's Ephemeris, which the Cross family then owned until 1985 when it was sold to W. Foulsham & Co,the Publisher. In Raphael's Ephemeris for 1913 he wrote: "Nothing has prospered with me except astrology...I have succeeded beyond my expectations..." In 1893, Cross's almanac sold 200,000 copies.

The time scale represented by Teph is closely related to, but distinct (by an offset and constant rate) from, the TCB time scale currently adopted as a standard by the IAU (see below: JPL ephemeris time argument Teph).E M Standish (1998). Most of the following sections relate to the ephemeris time of the 1952 standard. An impression has sometimes arisen that ephemeris time was in use from 1900: this probably arose because ET, though proposed and adopted in the period 1948–1952, was defined in detail using formulae that made retrospective use of the epoch date of 1900 January 0 and of Newcomb's Tables of the Sun.

In view of the fluctuation term, practical determination of the difference between ephemeris time and UT depended on observation. Inspection of the formulae above shows that the (ideally constant) unit of ephemeris time such as the ephemeris second has been for the whole of the twentieth century very slightly shorter than the corresponding (but not precisely constant) unit of mean solar time (which besides its irregular fluctuations tends gradually to increase), consistently also with the modern results of Morrison and StephensonL V Morrison & F R Stephenson (2004); also F R Stephenson, L V Morrison (1984), and F R Stephenson, L V Morrison (1995). (see article ΔT).

Baltimore: M. K. Goddard: Philadelphia: Benjamin January." (3) Drake, p. 215. "ELLICOTT'S Pennsylvania, Delaware, Maryland and Virginia Almanack and Ephemeris for 1786. Baltimore: Goddard and Langworthy.

Ephemeris by Abraham Zacuto in Almanach Perpetuum, 1496 The successive expeditions and experience of the Portuguese pilots led to a rapid evolution of Portuguese nautical science.

Their mass, consequently, is uncertain by about a factor of 10. For near-Earth asteroids without a well-determined diameter, Sentry assumes a generic albedo of 0.15. In August 2013, the Sentry Risk Table started using planetary ephemeris (DE431) for all NEO orbit determinations. DE431 (JPL small-body perturber ephemeris: SB431-BIG16) better models the gravitational perturbations of the planets and includes the 16 most massive main-belt asteroids.

In 1958, data was published linking the frequency for the caesium transition, newly established, with the ephemeris second. The ephemeris second is a unit in the system of time that, when used as the independent variable in the laws of motion that govern the movement of the planets and moons in the solar system, enables the laws of motion to accurately predict the observed positions of solar system bodies.

Also published by Smith was The Familiar Astrologer and A Manual of Astrology, both in 1828. Smith died on 26 February 1832 in London. His almanac continued to be edited as Raphael’s Ephemeris and would become a standard work in British and US American astrology. Raphael's Ephemeris popularized the system of Placidian system of astrological houses in the English-speaking world and in modern western astrology in general.

The astronomical unit of length was determined by the condition that the measured data in the ephemeris match observations, and that in turn decides the transit time τA.

349 + 72^s.3165T +29^s.949T^2 + 1.821B . . . . . (4) Clemence's formula, now superseded by more modern estimations, was included in the original conference decision on ephemeris time.

MPEC 2000-Y16: S/1975 J 1 = S/2000 J 1, S/1999 J 1 2000-12-19 (discovery and ephemeris) It was the 17th confirmed moon of Jupiter.

390–391 The American Ephemeris was the last to add a multi-year table, in 1925 with 2,000 years.American Ephemeris 1925, pp. 746–749 However, it was the first to include any mention of Julian days with one for the year of issue beginning in 1855, as well as later scattered sections with many days in the year of issue. It was also the first to use the name "Julian day number" in 1918.

A chapter from an as-yet-unpublished (Feb 2012) version of the Explanatory Supplement (see Sources) The independent variable of the ephemeris is always time. In the case of the most current ephemerides, it is a relativistic coordinate time scale equivalent to the IAU definition of TCB. In the past, mean solar time (before the discovery of the non-uniform rotation of the Earth) and ephemeris time (before the implementation of relativistic gravitational equations) were used. The remainder of the ephemeris can consist of either the mathematical equations and initial conditions which describe the motions of the bodies of the Solar System, of tabulated data calculated from those equations and conditions, or of condensed mathematical representations of the tabulated data.

Ephemeris time was consequently developed as a standard that was free from the irregularities of Earth rotation, by defining the time "as the independent variable of the equations of celestial mechanics", and it was at first measured astronomically, relying on the existing gravitational theories of the motions of the Earth about the Sun and of the Moon about the Earth. After the caesium atomic clock was invented, such clocks were used increasingly from the late 1950s as secondary realizations of ephemeris time (ET). These secondary realizations improved on the original ET standard by the improved uniformity of the atomic clocks, and (e.g. in the late 1960s) they were used to provide standard time for planetary ephemeris calculations and in astrodynamics.

He taught at Pennsylvania State College before joining the United States Naval Observatory in 1936, working under Paul Sollenberger and Gerald Clemence in the time service department. After having married Rosalyn Shulemson in 1943, Markowitz eventually became director of the department. He developed the ephemeris time scale, which had been adopted by the IAU in 1952 on a proposal formulated by Clemence in 1948,See references (incl. citations to some of Markowitz's papers) in article Ephemeris time.

An ephemeris day is a period of 86,400 SI seconds. The actual length of a solar day varies, and has a tendency to get longer as the tides slow the Earth down (see Tidal acceleration). In the Système International (SI), the length of day during the late 19th century was used to define the second. (See ΔT.) In recent decades, the length of a solar day has usually been a couple of milliseconds more than an ephemeris day.

Ephemerides of the planet Saturn also sometimes contain the apparent inclination of its ring. Celestial navigation serves as a backup to the Global Positioning System. Software is widely available to assist with this form of navigation; some of this software has a self-contained ephemeris. When software is used that does not contain an ephemeris, or if no software is used, position data for celestial objects may be obtained from the modern Nautical Almanac or Air Almanac.

718–722 The British Nautical Almanac began in 1879 with 2,000 years.Nautical Almanac and Astronomical Ephemeris 1879, p. 494 The Berliner Astronomisches Jahrbuch began in 1899 with 2,000 years.Berliner Astronomisches Jahrbuch 1899, pp.

By the 1950s it had become clear that the Earth's rotation rate was not constant, so astronomers developed ephemeris time, a time scale based on the positions of solar system bodies in their orbits.

After this incorporation the Itureans furnished soldiers for the Roman army; and the designations Ala I Augusta Ituraeorum and Cohors I Augusta Ituraeorum are met with in the inscriptions (Ephemeris Epigraphica, 1884, p. 194).

An invariable second (the "ephemeris second") had been defined, use of which removed the errors in ephemerides resulting from the use of the variable mean solar second as the time argument. In 1960 this ephemeris second was made the basis of the "coordinated universal time" which was being derived from atomic clocks. It is a specified fraction of the mean tropical year as at 1900 and, being based on historical telescope observations, corresponds roughly to the mean solar second of the early nineteenth century.

The satellite broadcasts a signal that contains orbital data (from which the position of the satellite can be calculated) and the precise time the signal was transmitted. Orbital data include a rough almanac for all satellites to aid in finding them, and a precise ephemeris for this satellite. The orbital ephemeris is transmitted in a data message that is superimposed on a code that serves as a timing reference. The satellite uses an atomic clock to maintain synchronization of all the satellites in the constellation.

Explanatory Supplement to the Astronomical Ephemeris, (London, 1961), sect.7B & 7D, pp. 178, 190. Hansen twice visited Britain and was twice (in 1842 and 1860) the recipient of the Gold Medal of the Royal Astronomical Society.

61–69, is an ephemeris of these phenomena that uses a base date of 1.18.1.8.0.16 in the prior era (5,482,096 days).Beyer, Hermann 1933 Emendations of the 'Serpent Numbers' of the Dresden Maya Codex. Anthropos (St.

A few years later, with the invention of the cesium atomic clock, an alternative offered itself. Increasingly, after the calibration in 1958 of the cesium atomic clock by reference to ephemeris time, cesium atomic clocks running on the basis of ephemeris seconds began to be used and kept in step with ephemeris time. The atomic clocks offered a further secondary realization of ET, on a quasi-real time basis that soon proved to be more useful than the primary ET standard: not only more convenient, but also more precisely uniform than the primary standard itself. Such secondary realizations were used and described as 'ET', with an awareness that the time scales based on the atomic clocks were not identical to that defined by the primary ephemeris time standard, but rather, an improvement over it on account of their closer approximation to uniformity.W G Melbourne & others, 1968, section II.E.4-5, pages 15-16, including footnote 7, noted that the Jet Propulsion Laboratory spacecraft tracking and data reduction programs of that time (including the Single Precision Orbit Determination Program) used, as ET, the current US atomic clock time A.1 offset by 32.25 seconds.

See G M Clemence's proposal of 1948, contained in his paper: "On the System of Astronomical Constants", Astronomical Journal (1948) vol.53 (6), issue #1170, pp 169–179; also G M Clemence (1971), "The Concept of Ephemeris Time", in Journal for the History of Astronomy v2 (1971), pp. 73–79 (giving details of the genesis and adoption of the ephemeris time proposal); also article Ephemeris time and references therein. Newcomb's tables formed the basis of all astronomical ephemerides of the Sun from 1900 through 1983: they were originally expressed (and published) in terms of Greenwich Mean Time and the mean solar day,Newcomb's Tables of the Sun (Washington, 1895), Introduction, I. Basis of the Tables, pp. 9 and 20, citing time units of Greenwich Mean Noon, Greenwich Mean Time, and mean solar dayW de Sitter, on p.

See Having done so, he and others soon discovered over the course of a few years, those equations of motion did not predict some orbits correctly or even very well.Rudolf Kurth has an extensive discussion in his book (see References) on planetary perturbations. An aside: these mathematically undefined planetary perturbations (wobbles) still exist undefined even today and planetary orbits have to be constantly updated, usually yearly. See Astronomical Ephemeris and the American Ephemeris and Nautical Almanac, prepared jointly by the Nautical Almanac Offices of the United Kingdom and the United States of America.

They are published by the Jet Propulsion Laboratory as Development Ephemeris. The latest releases include DE430 which covers planetary and lunar ephemeris from Dec 21, 1549 to Jan 25, 2650 with high precision and is intended for general use for modern time periods . DE431 was created to cover a longer time period Aug 15, -13200 to March 15, 17191 with slightly less precision for use with historic observations and far reaching forecasted positions. DE432 was released as a minor update to DE430 with improvements to the Pluto barycenter in support of the New Horizons mission.

Graphic rapresentation of JPL Horizons On-Line Ephemeris System output values JPL Horizons On-Line Ephemeris System provides easy access to key Solar System data and flexible production of highly accurate ephemerides for Solar System objects. Osculating elements at a given epoch are always an approximation to an object's orbit (i.e. an unperturbed conic orbit or a "two-body" orbit). The real orbit (or the best approximation to such) considers perturbations by all planets, a few of the larger asteroids, a few other usually small physical forces, and requires numerical integration.

Data may be based on each planet's true center or its barycenter. The use of Chebyshev polynomials enables highly precise calculations for a given point in time. DE405 recovery (calculation) for the inner planets is about 0.001 arcseconds (equivalent to about 1 km at the distance of Mars); for the outer planets it is generally about 0.1 arcseconds. The 'reduced accuracy' DE406 ephemeris gives an interpolating precision (relative to the full ephemeris values) no worse than 25 metres for any planet and no worse than 1 metre for the moon.

It included additional ranging and VLBI measurements of Mars spacecraft, new ranging and VLBI of the Venus Express spacecraft, the latest estimates of planetary masses, additional lunar laser ranging, and two more months of CCD measurements of Pluto. When initially released in 2008, the DE421 ephemeris covered the years 1900 to 2050. An additional data release in 2013 extended the coverage to the year 2200. DE422 was created in 2009 for the MESSENGER mission to Mercury. A Long Ephemeris, it was intended to replace DE406, covering 3000 BC to AD 3000.

Morrison The printers had published many of these almanacs during more than one year. The Check List showed that 18 of the almanacs had been printed in Maryland, including Ellicott's Maryland and Virginia Almanack for 1787 and 1789 and Ellicott's Maryland and Virginia almanac and ephemeris for 1791, each of which John Hayes of Baltimore had printed.Morrison, pp. 30-31. William Goddard of Baltimore, who later printed Banneker's 1792 almanac, had printed The Pennsylvania, Delaware, Maryland and Virginia almanack and ephemeris for each year from 1784 to 1790, except 1786.

In 1976 the IAU resolved that the theoretical basis for its current (1952) standard of Ephemeris Time was non-relativistic, and that therefore, beginning in 1984, Ephemeris Time would be replaced by two relativistic timescales intended to constitute dynamical timescales: Terrestrial Dynamical Time (TDT) and Barycentric Dynamical Time (TDB).IAU resolutions (1976); see also ESAA (1992) at p.41. Difficulties were recognized, which led to these being in turn superseded in the 1990s by time scales Terrestrial Time (TT), Geocentric Coordinate Time GCT(TCG) and Barycentric Coordinate Time BCT(TCB).

Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data.

WinStars is an ASCOM standard-compliant shareware planetarium, ephemeris and solar system simulator developed by Richard Franck for the Android, iOS, Linux, OSX, and Microsoft Windows operating systems. WinStars functionality includes the ability to control computerized GoTo telescope mounts.

This work led Essen to champion the caesium spectrum as an international time standard. The ammonia molecule had already been proposed as such but Essen was convinced that caesium would prove more stable. However, the International Astronomical Union meeting in Rome in 1952 had adopted the ephemeris time scale, on a proposal by Gerald Clemence defining the time unit in terms of the Earth's motion round the sun. The ephemeris second, based on a fraction of the tropical year derived from Simon Newcomb's expression for the mean solar motion, became a standard in 1960, but in 1967, at the 13th Conférence Générale des Poids et Mesures, the second was redefined in terms of a value for the ephemeris second that had been precisely measured by Essen in collaboration with William Markowitz of the United States Naval Observatory in terms of the frequency of a chosen line from the spectrum of caesium.

As of August 2013 (planetary ephemeris DE431) close-approach data is available for the major planets and the 16 most massive asteroids. Close approach data is available by adding ";cad=1" or "&cad;=1" to the end of the body's URL.

Leningrad Blockade Museum (Rumyantsev Mansion), Saint Petersburg 2001 — Daedaluses and Icaruses. National Reserve Bank, Moscow 2001 — In-depth Germany. Na Kashirke Exhibition Hall, Moscow 2000 — CLAVA's Lovers (Avant- Garde Club exhibition at Art Moscow). Central House of Artists, Moscow 2000 — Ephemeris.

The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (more exactly, when the ecliptic longitudes of the Sun and Moon differ by 180°).[P. Kenneth Seidelmann (ed.), "Phases of the Moon", Explanatory Supplement to the Astronomical Almanac: A Revision to the Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac, (Mill Valley: University Science Books, 1992), p. 478. This means that the lunar hemisphere facing Earth – the near side – is completely sunlit and appears as a circular disk.

The receiver knows the receiver clock time of when the beginning of the next subframe was received from detection of the Telemetry Word thereby enabling computation of the transit time and thus the pseudorange. The receiver is potentially capable of getting a new pseudorange measurement at the beginning of each subframe or every 6 seconds. Then the orbital position data, or ephemeris, from the navigation message is used to calculate precisely where the satellite was at the start of the message. A more sensitive receiver will potentially acquire the ephemeris data more quickly than a less sensitive receiver, especially in a noisy environment.

On 18 July 1765 the Board of Longitude (effectively led by Nevil Maskelyne) appointed Dunthorne as the first "Comparer of the Ephemeris and Corrector of the Proofs" for the (then still future) Nautical Almanac and Astronomical Ephemeris. The first issue appeared with data for the year 1767, breaking new ground in providing computational tools to enable mariners to use lunar observations to find their longitude at sea.M Croarken, 2002. Dunthorne worked as sole comparer for the first three issues, with data for 1767–69, and afterward continued as one of several comparers until the issue for 1776.

Anthony à Wood believed that he studied at Oxford. He was living in London at the date of his first Ephemeris (1556), and appears, from a remark in a manuscript in Lambeth Palace Library, to have been a public instructor in science.

In 1967 the SI second was made equal to the ephemeris second.Leap seconds by USNO The apparent solar time is a measure of Earth's rotation and the difference between it and the mean solar time is known as the equation of time.

It is also the basis for computing the geometrical albedo and the Bond albedo of the body. In ephemeris generation, the phase curve is used in conjunction with the distances from the object to the Sun and the Earth to calculate the apparent magnitude.

It was removed from service on 9 October 2019. Two of the satellites in this series, numbers 35 and 36, are equipped with laser retro-reflectors, allowing them to be tracked independently of their radio signals, providing unambiguous separation of clock and ephemeris errors.

The accuracy of the resulting range measurement is essentially a function of the ability of the receiver's electronics to accurately process signals from the satellite, and additional error sources such as non-mitigated ionospheric and tropospheric delays, multipath, satellite clock and ephemeris errors, etc.

Originally, the US Naval Observatory (USNO) continuously observed the precise orbits of these satellites. As a satellite's orbit deviated, the USNO sent the updated information to the satellite. Subsequent broadcasts from an updated satellite would contain its most recent ephemeris. Modern systems are more direct.

The set of physical laws and numerical constants used in the calculation of the ephemeris must be self- consistent and precisely specified. The ephemeris must be calculated strictly in accordance with this set, which represents the most current knowledge of all relevant physical forces and effects. Current fundamental ephemerides are typically released with exact descriptions of all mathematical models, methods of computation, observational data, and adjustment to the observations at the time of their announcement.See, for instance, ; ; This may not have been the case in the past, as fundamental ephemerides were then computed from a collection of methods derived over a span of decades by many researchers.

The second part contained data for the meridian of Washington on the Sun, Moon, planets, principal stars, eclipses, occultations, and other phenomena. Beginning in 1882, data for Mercury, Uranus, and Neptune was added to the first part, with eclipses, occultations, and other phenomena forming a separate third part. In 1916, The American Nautical Almanac ceased to be a reprint of the first part of the American Ephemeris and Nautical Almanac, becoming a separately prepared volume for the navigator. In 1937, the American Ephemeris and Nautical Almanac was divided into seven parts, with data for the meridian of Washington substantially reduced, then eliminated beginning in 1951.

The zodiac signs in a 16th-century woodcut A volvella of the moon. A volvella is a moveable device for working out the position of the Sun and Moon in the zodiac, 15th century 17th-century fresco of Christ in the Zodiac circle, Cathedral of Living Pillar, Georgia An example of the use of signs as astronomical coordinates may be found in the Nautical Almanac and Astronomical Ephemeris for the year 1767. The "Longitude of the Sun" columns show the sign (represented as a digit from 0 to and including 11), degrees from 0 to 29, minutes, and seconds.Nautical Almanac and Astronomical Ephemeris for the year 1767.

This minor planet is named in honor of Russian astronomer and geodesist Ivan Danilovich Zhongolovich, who was the head of the Special Ephemeris Department at the Institute of Theoretical Astronomy (ITA) in St Petersburg. The official was published by the Minor Planet Center on 20 February 1976 ().

Explanatory Supplement (1961), sec. 2B From 1984, the Jet Propulsion Laboratory's DE series of computer-generated ephemerides took over as the fundamental ephemeris of the Astronomical Almanac. Obliquity based on DE200, which analyzed observations from 1911 to 1979, was calculated: where hereafter is Julian centuries from J2000.0.

On October 8, 2013 the SETI Institute announced that Naiad had been located in archived Hubble imagery from 2004. The suspicion that the loss of positioning was due to considerable errors in Naiad's ephemeris proved correct as Naiad was ultimately located 80 degrees from its expected position.

A single reference geographically close to the target will give a high degree of cancellation of the location effects of ephemeris error. Measurements on signals from multiple reference sites can be used to improve the accuracy of the satellite ephemerides thereby provided improved geolocation accuracy generally.

These are the lengths of the various types of months as discussed above (according to the lunar ephemeris ELP2000-85, valid for the epoch J2000.0; taken from (e.g.) Meeus (1991) ): : SM = 29.530588853 days (Synodic month)Meeus (1991) form. 47.1 : DM = 27.212220817 days (Draconic month)Meeus (1991) ch. 49 p.

Caquot, "Observations sur la Premiere Tablette Magique d'Arslan Tash", JANES 5 (1973), 45–51. and Röllig (1974).W. Röllig: "Die Amulette von Arslan Tash" in Neue Ephemeris für Semitische Epigraphik. Wiesbaden, 1974, Albright introduced some readings which have now been shown to be incorrect; modern scholarship now follows Caquot.

Note that these precision numbers are for the interpolated values relative original tabulated coordinates. The overall precision and accuracy of interpolated values for describing the actual motions of the planets will be a function of both the precision of the ephemeris tabulated coordinates and the precision of the interpolation.

In 1976, however, the IAU resolved that the theoretical basis for ephemeris time was wholly non- relativistic, and therefore, beginning in 1984 ephemeris time would be replaced by two further time scales with allowance for relativistic corrections. Their names, assigned in 1979, emphasized their dynamical nature or origin, Barycentric Dynamical Time (TDB) and Terrestrial Dynamical Time (TDT). Both were defined for continuity with ET and were based on what had become the standard SI second, which in turn had been derived from the measured second of ET. During the period 1991–2006, the TDB and TDT time scales were both redefined and replaced, owing to difficulties or inconsistencies in their original definitions.

Galileo attempted to produce a table predicting the positions of the Jovian satellites and eclipse timings after he negotiated first with Spain and then with The Netherlands to create a system for measuring longitude at sea using eclipse timings. However, he was never able to generate accurate predictions far enough ahead in time to be useful so he never published his tables. This left the tables published by Simon Marius in Mundus Iovialis and Giovanni Battista Hodierna in 1654 as the most accurate ephemeris tables available, even though they too were unable to predict the moons' positions with sufficient accuracy. Giovanni Cassini published a much more accurate ephemeris table in 1668 using his observations from the previous 16 years.

Successive definitions of the unit of ephemeris time are mentioned above (History). The value adopted for the 1956/1960 standard second: :the fraction 1/31 556 925.9747 of the tropical year for 1900 January 0 at 12 hours ephemeris time. was obtained from the linear time-coefficient in Newcomb's expression for the solar mean longitude (above), taken and applied with the same meaning for the time as in formula (3) above. The relation with Newcomb's coefficient can be seen from: :1/31 556 925.9747 = 129 602 768.13 / (360×60×60×36 525×86 400). Caesium atomic clocks became operational in 1955, and quickly confirmed the evidence that the rotation of the earth fluctuated randomly.

'Autonoe , also known as ', is a natural satellite of Jupiter. Autonoe was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the temporary designation '.IAUC 7900: Satellites of Jupiter 2002 May 16 (discovery)MPEC 2002-J54: Eleven New Satellites of Jupiter 2002 May 15 (discovery and ephemeris)MPEC 2002-V03: S/2001 J 1 2002 November 1 (revised ephemeris) Autonoe is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 24,264,000 km in 772.168 days. It orbits at an inclination of 151° to the ecliptic (150° to Jupiter's equator) in a retrograde direction and with an eccentricity of 0.369.

Many theoligans and scholars also thought that it went against the tenets of Islam; as only God should be able to determine events rather than astrologers looking at the positions of the planets. In order to calculate someone's horoscope, an astrologer would use 3 tools: an astrolabe, ephemeris and a takht. First, the astrologer would use an astrolabe to find the position of the sun, align the rule with the persons time of birth and then align the rete to establish the altitude of the sun on that date. Next, the astrologer would use an Ephemeris, a table denoting the mean position of the planets and stars within the sky at any given time.

The stones are outlining a ship. Here we show > the well-known alignment of this ship along the sunset direction on summer > solstice. We propose also alignments of the stones along the northern > possible moonset on major and minor lunar standstills. These astronomical > alignments are shown using the Photographer's Ephemeris.

Whilst visiting the sick there he became ill and died in 1704. He was buried at Hatfield. De la Pryme began keeping a diary--Ephemeris Vitae: A Diary of My Own Life--at the age of twelve and continued it until his death. This diary was published by the Surtees Society in 1870.

Jet Propulsion Laboratory (JPL) ephemerides do not use things such as periods, eccentricities, etc. Instead, JPL integrates the equations of motion in Cartesian coordinates (x,y,z), and adjusts the initial conditions in order to fit modern, highly accurate measurements of planetary positions. As of August 2015, Horizons now uses ephemeris DE431.

11, § 3. the Iturean kingdom lay north of Galilee. That Itureans dwelt in the region of Mount Lebanon is confirmed by an inscription of about the year 6 CE (Ephemeris Epigraphica, 1881, pp. 537–542), in which Quintus Aemilius Secundus relates that he was sent by Quirinius against the Itureans in Mount Lebanon.

After leaving the planetary region of the Solar System, the post-perihelion orbital period is estimated to be about 78,000 years with aphelion around 3,650 AU. (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0) In 2007 it became more than 30 AU from the Sun.

In 1869 he became a professor at the University of Vienna. He was named the director of the Vienna Observatory in 1878. He also served as president of the Austrian österreichischen Gradmessungskommission, the degree measurement commission. He published a number of comet observations and ephemeris' in the Astronomische Nachrichten between 1859 and 1909.

Partly in acknowledgement of the widespread use of Teph via the JPL ephemerides, IAU resolution 3 of 2006IAU 2006 resolution 3 (re-)defined Barycentric Dynamical Time (TDB) as a current standard. As re-defined in 2006, TDB is a linear transformation of TCB. The same IAU resolution also stated (in note 4) that the "independent time argument of the JPL ephemeris DE405, which is called Teph" (here the IAU source cites), "is for practical purposes the same as TDB defined in this Resolution". Thus the new TDB, like Teph, is essentially a more refined continuation of the older ephemeris time ET and (apart from the periodic fluctuations) has the same mean rate as that established for ET in the 1950s.

An almanac maker going under the pseudonym of Poor Richard, Knight of the Burnt Island began to publish Poor Robin's Almanack one of the first comic almanacs that parodied these horoscopes in its 1664 issue, saying "This month we may expect to hear of the Death of some Man, Woman, or Child, either in Kent or Christendom." Other noteworthy comic almanacs include those published from 1687-1702 by John Tully of Saybrook, Connecticut. The Boston ephemeris was an early almanac published in Boston during the 1680s.The Boston ephemeris: an almanack for the year MDCLXXXIV, and of the worlds creation 5633, oppidi inchoati, 55; being the first after leap-year, of which the vulgar notes are ... calculated for the meridian of Boston in New-Engl.

Its observation by CoRoT provided an extremely high quality ligthcurve. Global parameters could then be improved and new ephemeris for the orbital motion as well as for another long term variation were derived. This long period variation seems to originate from a periodic light attenuation by circumstellar dust. The light curve of HD 174884.

In this way, decisions made by the original designers of ephemeris time influenced the length of today's standard SI second, and in turn, this has a continuing influence on the number of leap seconds which have been needed for insertion into current broadcast time scales, to keep them approximately in step with mean solar time.

Simon Newcomb (1898)Simon Newcomb, "Tables of the Motion of the Earth on its Axis and Around the Sun" in Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac, Volume VI: Tables of the Four Inner Planets, (United States Naval Observatory, 1898), pp. 27 & 34–35. and Fred Espenak (2007).

The Berliner Astronomisches Jahrbuch (abbrev. B.A.J.) is an astronomical ephemeris almanac and the longest publication series in astronomy. It was a compendium of ephemerides of all large Solar System bodies and of fundamental stars which define the celestial reference system. The B.A.J. series was founded by Johann Elert Bode, and is thus sometimes referred to as Bode's Astronomisches Jahrbuch.

At the age of 11, Joshi followed his father, Daibagya Krishna Raj Joshi's footsteps into astrology. The elder Joshi had edited and published Mangal Ephemeris for 77 yrs. Dr. Joshi also lent his presence to the education as a teacher at many colleges. His career began as a teacher at the Tri Chandra College in 1967.

Strings 1-4 provide immediate data for the transmitting satellite, and are repeated every frame; the data include ephemeris, clock and frequency offsets, and satellite status. Strings 5-15 provide non-immediate data (i.e. almanac) for each satellite in the constellation, with frames I-IV each describing five satellites, and frame V describing remaining four satellites.

Robert Thomas Cross (born 15 May 1850 in Worstead, d. 1923) was a British astrologer. Cross was one in a series of editors of Raphael's Ephemeris, started by Robert Cross Smith in 1827, who all took the pseudonym Raphael. Robert Thomas Cross is often confused with Robert Cross Smith due to the similarity in name and the identical pseudonym.

W. Foulsham & Company Limited is a British publisher founded by William Foulsham in 1819.About Us, foulsham.com. Retrieved 9 March 2018. It is the current publisher of Old Moore's Almanack, an annual publication first published in 1697, and of Raphael's Ephemeris, which Robert Thomas Cross acquired in the 1870s and edited until his death in 1913.

During his stay in Brussels Stadius published his first work, the Ephemerides novae et auctae, first published by the publisher Arnold Birckmann of Cologne in 1554. An ephemeris (plural: ephemerides) (from the Greek word ephemeros, "daily") was, traditionally, a table providing the positions (given in a Cartesian coordinate system, or in right ascension and declination or, for astrologers, in longitude along the zodiacal ecliptic), of the Sun, the Moon, and the planets in the sky at a given moment in time; the astrological positions are usually given for either noon or midnight depending on the particular ephemeris that is used. This work posited a link between mathematics and medicine and was influential on Tycho Brahe and Nostradamus. Stadius had been encouraged to publish the Ephemerides by his old teacher Gemma Frisius.

Decimus or Decimius Magnus Ausonius (; - c. 395) was a Roman poet and teacher of rhetoric from Burdigala in Aquitaine, modern Bordeaux, France. For a time he was tutor to the future emperor Gratian, who afterwards bestowed the consulship on him. His best-known poems are Mosella, a description of the river Moselle, and Ephemeris, an account of a typical day in his life.

It has an observation arc of 32 days and an orbital uncertainty of 7. Since the asteroid has a poorly known orbit, the cone of uncertainty quickly multiplies as a result of perturbations by the inner planets and prevents precise/reliable ephemeris data. Eliminating an entry on the Sentry Risk Table is a negative prediction; a prediction of where it will NOT be.

124, 314 The news report did not mention Banneker's name.(1) Bedini, 1969, p. 25. (2) ]}} . Banneker left the boundary survey in April 1791 within three months of its initiation because the time that he was devoting to the project was conflicting with the time that he had expected to use to calculate an ephemeris for the year of 1792.

After returning to Ellicott's Mills, Banneker made astronomical calculations that predicted eclipses and planetary conjunctions for inclusion in an almanac and ephemeris for the year of 1792.Bedini, 1999, pp. 147—188: "His First Almanac". To aid Banneker in his efforts to have his almanac published, Andrew Ellicott (who had been authoring almanacs and ephemerides of his own since 1780)(1) .

DE405 was released in 1998. It added several years' extra data from telescopic, radar, spacecraft, and VLBI observations (of the Galileo spacecraft at Jupiter, in particular). The method of modeling the asteroids' perturbations was improved, although the same number of asteroids were modeled. The ephemeris was more accurately oriented onto the ICRF. DE405 covered 1600 to 2200 to full precision.

StarFire broadcasts this data at 300 bits per second, repeating once a second. The corrections are generally valid for about 20 minutes. In addition to ephemeris and clock corrections, the signal also contains information on the health of each satellite, offering quality-of-service data in near real-time, with about a 3-second delay in updating the signals from the ground station.

In the United States, a nautical almanac has been published annually by the US Naval Observatory since 1852. It was originally titled American Ephemeris and Nautical Almanac. Since 1958, the USNO and HMNAO have jointly published a unified nautical almanac, the Astronomical Almanac for use by the navies of both countries. Almanac data is now available online from the US Naval Observatory.

Kondos reported the finds to authorities in Athens, and quickly Hellenic Navy vessels were sent to support the salvage effort from November 1900 through 1901.Ephemeris Archaeology, 1902Gladys Davidson Weinberg; Virginia R. Grace; G. Roger Edwards; Henry S. Robinson; Peter Throckmorton; Elizabeth K. Ralph "The Antikythera Shipwreck Reconsidered" Transactions of the American Philosophical Society, New Ser., Vol. 55, No. 3.

SPICE data files are usually referred to as "kernels." These files provide information such as spacecraft trajectory and orientation; target body ephemeris, size and shape; instrument field-of-view size, shape and orientation; specifications for reference frames; and tabulations of time system conversion coefficients. SPICE data are archived in a national archive center such as the NASA Planetary Data System archives.

This minor planet was named after Russian astronomer Valerij Valyaev (b. 1944), chief of the Ephemeris Astronomy Department at the Institute for Theoretical Astronomy (ITA), which was then part of the USSR Academy of Sciences in Leningrad. The minor planet 1735 ITA is named after this institute. Valyaev is also the senior editor of the periodicals Morskoj Astronomicheskij Ezhegodnik and Aviatsionnyj Astronomicheskij Ezhegodnik.

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.

From Athens she launched the feminist movement in Greece with the founding of a newspaper, Ephemeris ton kyrion (Ladies' Journal), in 1887.Ahmet Ersoy, Macie J. Gorny, Vangelis Kechriotis, (eds), Modernism: The Creation of Nation States., pp. 125–130. Central European University Press, (October 28, 2010), This was a publication run entirely by women and appeared initially as an 8 pg.

Balbus kept a diary of the chief events in his own and Caesar's life (Ephemeris), which has been lost (Suetonius, Caesar, 81). He took care that Caesar's Commentaries on the Gallic War should be continued; and accordingly the 8th book of the Commentarii de Bello Gallico (which was probably written by his friend Hirtius at his instigation) is dedicated to him.

Georgij A. Krasinsky (February 19, 1939; Leningrad, USSR) – March 17, 2011) was a Russian astronomer active at the Institute of Applied Astronomy, Russian Academy of Science, St Petersburg. He was notable for research on planetary motions and ephemeris. Krasinsky was the president of IAU commission 4-DI on ephemerides during 2003-2006. The asteroid 5714 Krasinsky is named after him.

72 (1967), p.1324-6. and overall will remain at less than 2 milliseconds for several millennia.IAU 2006 resolution 3, see Recommendation and footnotes, note 3. TDB applies to the Solar-System-barycentric reference frame, and was first defined in 1976 as a successor to the (non-relativistic) former standard of ephemeris time (adopted by the IAU in 1952 and superseded 1976).

Thus, the Government of India has prepared the National Panchānga or the Indian national calendar in 1957 (was proposed by Meghnad Saha and Lahiri in 1952), which is used in predictive astrology. The Lahiris Ephemeris published annually is the most widely used English almanac in Vedic astrology, many Panchāngas are published in local languages, which are mostly based on the National Panchānga.

Karl was born in the Free Imperial City of Rothenburg, which is now called Rothenburg ob der Tauber in Germany. From 1814 he studied in Gymnasium in Ausbach. He attended the University of Göttingen from 1818 to 1822 where he studied with Gauss who was director of the observatory. Staudt provided an ephemeris for the orbits of Mars and the asteroid Pallas.

That value was chosen so that the caesium second equalled, to the limit of human measuring ability in 1960 when it was adopted, the existing standard ephemeris second based on the Earth's orbit around the Sun. Because no other measurement involving time had been as precise, the effect of the change was less than the experimental uncertainty of all existing measurements.

Chaldene , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al., in 2000, and given the temporary designation '.IAUC 7555: Satellites of Jupiter 2001 January 5 (discovery)MPEC 2001-A29: S/2000 J 7, S/2000 J 8, S/2000 J 9, S/2000 J 10, S/2000 J 11 2001 January 15 (discovery and ephemeris)MPEC 2001-T59: S/2000 J 8, S/2000 J 9, S/2000 J 10 2001 October 15 (revised ephemeris) Chaldene is about 3.8 kilometres in diameter, and orbits Jupiter at an average distance of 22,713,000 km in 699.327 days, at an inclination of 167° to the ecliptic (169° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2916.

Taygete , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al. in 2000, and given the temporary designation '.IAUC 7555: Satellites of Jupiter 2001 January 5 (discovery)MPEC 2001-A29: S/2000 J 7, S/2000 J 8, S/2000 J 9, S/2000 J 10, S/2000 J 11 2001 January 15 (discovery and ephemeris)MPEC 2001-T59: S/2000 J 8, S/2000 J 9, S/2000 J 10 2001 October 15 (revised ephemeris) Taygete is about 5 kilometres in diameter, and orbits Jupiter at an average distance of 22,439,000 km in 686.675 days, at an inclination of 165° to the ecliptic (163° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.3678.

In 1945 he hired Herb Grosch and Llewellyn Thomas as the next two IBM research scientists, who both made significant contributions. When Cuthbert Hurd became the next PhD to be hired by IBM in 1949, he was offered a position with Eckert, but instead founded the Applied Science Department, and later directed the development of IBM's first commercial stored program computer (the IBM 701) based on the demand demonstrated by applications such as those of Eckert. In this period he continued his innovative contributions to computational astronomy by implementing Brown's Lunar theory in his computer; developing the Improved Lunar Ephemeris; and performing the first numerical integration to compute an ephemeris for the outer planets. In 1957 the Watson lab moved to Yorktown Heights, New York (with a new building completed in 1961) where it is known as the Thomas J. Watson Research Center.

He would continue teaching in Missouri and Tennessee until 1858. At that point, he took up a full-time position on the staff of American Ephemeris and Nautical Almanac in Cambridge, Massachusetts. In 1882, Ferrel joined the U.S. Army Signal Service (which would become the Weather Bureau in 1891) and retired in 1886. He died in Maywood (Wyandotte county), a suburb of Kansas City, in 1891..

Satellite data is updated typically every 24 hours, with up to 60 days data loaded in case there is a disruption in the ability to make updates regularly. Typically the updates contain new ephemerides, with new almanacs uploaded less frequently. The Control Segment guarantees that during normal operations a new almanac will be uploaded at least every 6 days. Satellites broadcast a new ephemeris every two hours.

The jumps increased in size to 0.1 second. This UTC was intended to permit a very close approximation to UT2. In 1967, the SI second was redefined in terms of the frequency supplied by a caesium atomic clock. The length of second so defined was practically equal to the second of ephemeris time. This was the frequency that had been provisionally used in TAI since 1958.

DE403 covered the time span early 1599 to mid 2199. DE404 was released in 1996. A so-called Long Ephemeris, this condensed version of DE403 covered 3000 BC to AD 3000. While both DE403 and DE404 were integrated over the same timespan, the interpolation of DE404 was somewhat reduced in accuracy and nutation of the Earth and libration of the Moon were not included.

It was discovered on 23 May 2012 by the Mount Lemmon Survey at an apparent magnitude of 20.8 using a reflecting telescope. On 28 May 2012 at 15:20 UT, the asteroid passed from the center-point of Earth. The asteroid is estimated to be in diameter. It was removed from the Sentry Risk Table on 8 August 2013 after Sentry updated to planetary ephemeris (DE431).

25–27, p.271. Buckingham, searching for Biela's Comet using an ephemeris provided by John Russell Hind, described having found "two round vapoury bodies" in approximately the right position; however Hind later communicated to him that he thought the observation might have been of two nebulae. might have been the same object as that seen by Pogson, and suggested an 1893 return, which did not occur.Kronk, p.

Nourse became apprenticed to William Mears as a bookseller. His brother, the surgeon Charles Nourse took over the business when he died. His premises were at the Old King's Arms opposite Catherine Street on the Strand, London. He was licensed to publish the first Nautical Almanac and Astronomical Ephemeris, dated 1766, but actually appearing in 1767, as evinced by correspondence between Nevil Maskelyne and Nourse.

R. Hide et al., "Topographic core-mantle coupling and fluctuations in the Earth's rotation" 1993. The mean solar second between 1750 and 1892 was chosen in 1895 by Simon Newcomb as the independent unit of time in his Tables of the Sun. These tables were used to calculate the world's ephemerides between 1900 and 1983, so this second became known as the ephemeris second.

Within the context of Coordinated Universal Time (UTC) it was the longest year ever, as two leap seconds were added during this 366-day year, an event which has not since been repeated. (If its start and end are defined using mean solar time [the legal time scale], its duration was 31622401.141 seconds of Terrestrial Time (or Ephemeris Time), which is slightly shorter than 1908).

As it detects each satellite's signal, it identifies it by its distinct C/A code pattern. There can be a delay of up to 30 seconds before the first estimate of position because of the need to read the ephemeris data. Processing of the navigation message enables the determination of the time of transmission and the satellite position at this time. For more information see Demodulation and Decoding, Advanced.

GPS signals include ranging signals, used to measure the distance to the satellite, and navigation messages. The navigation messages include ephemeris data, used to calculate the position of each satellite in orbit, and information about the time and status of the entire satellite constellation, called the almanac. There are four signals available for civilian use. In order of date of introduction, these are: L1 C/A, L2C, L5 and L1C.

The department which produced only five advanced degrees prior to 1951 graduated 29 Masters and 14 Doctoral student during the McVittie administration. On October 4, 1957, the very evening of the launch of Sputnik, students and faculty met at the Observatory and constructed an improvised radio interferometer. They published the first precise ephemeris in Nature in November. Their success helped gather momentum and funding for the radio astronomy program.

In the 285 years from 1953 to 2238 it makes 72 orbits, giving an average period of 3.96 years (quite close to a third of Jupiter's period, which comes to 3.95 years).NASA ephemeris calculator Its Earth Minimum orbit intersection distance (MOID) is 0.1102 AU which translates into 42.9 lunar distances. On 24 February 2062, it will make a close approach and pass by Earth at a distance of .

From 2015 onwards this ephemeris is utilized in Astronomical Almanac. Beginning with this release only Mars' Barycenter was included due to the small masses of its moons Phobos and Deimos which create a very small offset from the planet's center. The complete ephemerides files is 128 megabytes but several alternative versions have been made available by JPL DE432 was created April 2014. It includes librations but no nutations.

Portrait of David Origanus by Heinrich Jakob Otto. David Origanus or David Tost (9 July 1558 - 11 July 1628/29) was a German astronomer and professor for Greek language and Mathematics at the Viadrina University in Frankfurt (Oder), where he had also studied. Tost was born in Glatz (Kladsko), Bohemia (now Kłodzko in southern Poland). During his scientific career he observed numerous comets and published about Ephemeris in 1599 and 1609.

This minor planet was named after American astronomer Harold D. Ables (born 1938). While director at the United States Naval Observatory Flagstaff Station (NOFS), he was responsible for the station's transition from photographic plates to CCD imaging. The body's name was suggested by the JPL Ephemeris Group and subsequently proposed by the discoverers. The approved naming citation was published by the Minor Planet Center on 1 July 1996 .

His "Guide to Astrology", published in two volumes in 1877 and 1879 was widely used by astrologers for many years. In 1895 the Astrologer's Magazine quoted Cross for his support of the idea of forming an astrological society. On 14 January 1896 Alan Leo founded a society with himself as the first president and Cross as vice-president. Raphael's Ephemeris continues to be published, with W. Foulsham & Company Limited.

Its "blue light" source star tracker, which could see stars during both day and night, would continuously track a variety of stars as the aircraft's changing position brought them into view. The system's digital computer ephemeris contained data on a list of stars used for celestial navigation: the list first included 56 stars, and was later expanded to 61."SR-71A-1 Flight Manual, Section IV, p. 3." sr-71.org.

He used it to make further observations of satellites of Mars and Saturn, and was able to see Saturn's moon Mimas and show that the ephemeris of its orbit was incorrect. With this instrument he also obtained a photograph of a comet in 1881, C/1881 K1. His most notable work with this telescope were the long time exposures he made of the Orion Nebula between 1880 and 1884.

The results varied throughout the year, which required corrections. To address this the Portuguese used the astronomical tables (Ephemeris), a precious tool for oceanic navigation, which spread widely in the fifteenth century. These tables revolutionized navigation, enabling latitude calculations. The tables of the Almanach Perpetuum, by astronomer Abraham Zacuto, published in Leiria in 1496, were used along with its improved astrolabe, by Vasco da Gama and Pedro Alvares Cabral.

The entry system would have been tracked and targeted utilizing a combination of Doppler radar and very long baseline interferometry. This data would processed by a high-resolution orbital model that utilizes high-precision ephemeris to predict spacecraft location and trajectory. Upon launch, tracking would commence at the Algonquin Radio Observatory. After orbital injection, the spacecraft would be contacted periodically to obtain system status and to determine trajectory.

In astronomy and celestial navigation, an ephemeris (plural: ephemerides) gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky, i.e., the position (and possibly velocity) over time. The etymology is and .. Historically, positions were given as printed tables of values, given at regular intervals of date and time. The calculation of these tables was one of the first applications of mechanical computers.

An ephemeris is usually only correct for a particular location on the Earth. In many cases, the differences are too small to matter. However, for nearby asteroids or the Moon, they can be quite important. Other modern ephemerides recently created are the EPM (Ephemerides of Planets and the Moon), from the Russian Institute for Applied Astronomy of the Russian Academy of Sciences, and the INPOP (') by the French IMCCE.

Not held at USAF Museum). Later, to improve the accuracy of the deorbit commands, orbital analysts Lt Algimantas Šimoliūnas, Lawrence Cuthbert, or Ed Casey would update the Space Track ephemeris for each Discoverer at the last minute and send the update to the 6594th. The 6594th had a global network of tracking stations (including Alaska, Hawaii, Seychelles, Guam, and the UK), used for command and on-orbit control of the satellites.

Although Kouroi have been found in many ancient Greek territories, they were especially prominent in Attica and Boiotia. The term kouros was first proposed for what were previously thought to be depictions of Apollo by V. I. Leonardos in 1895 in relation to the youth from Keratea,Archaeologike Ephemeris, 1895, col. 75, n. 1. and adopted by Henri Lechat as a generic term for the standing male figure in 1904.

In 1967 a further step was taken with the introduction of the SI second, essentially the ephemeris second as measured by atomic clocks and formally defined in atomic terms. The SI second (Standard Internationale second) is based directly on the measurement of the atomic-clock observation of the frequency oscillation of caesium atoms. It is the basis of all atomic timescales, e.g. coordinated universal time, GPS time, International Atomic Time, etc.

A former Coal-Collator from the Deep Coal Cellar in the Lower House. Pravuil's loyalty has appeared to change hands many times. After betraying Arthur in Mister Monday, he flees using an elevator, later appearing in Sir Thursday as a Major in the Glorious Army of the Architect. On Saturday's orders, he issues the changes to the Ephemeris of Colonel Trabizond Nage, which begins the New Nithling invasion.

Joseph Winlock (February 6, 1826 – June 11, 1875) was an American astronomer and mathematician. He was born in Shelby County, Kentucky, the grandson of General Joseph Winlock (1758–1831). After graduating from Shelby College in Kentucky in 1845, he was appointed professor of mathematics and astronomy at that institution. From 1852 until 1857 he worked as a computer for the American Ephemeris and Nautical Almanac, and relocated to Cambridge, Massachusetts.

IX Special perturbations can be applied to any problem in celestial mechanics, as it is not limited to cases where the perturbing forces are small. Once applied only to comets and minor planets, special perturbation methods are now the basis of the most accurate machine-generated planetary ephemerides of the great astronomical almanacs.See, for instance, Jet Propulsion Laboratory Development Ephemeris. Special perturbations are also used for modeling an orbit with computers.

Louis Essen The first accurate atomic clock, a caesium standard based on a certain transition of the caesium-133 atom, was built by Louis Essen and Jack Parry in 1955 at NPL. Calibration of the caesium standard atomic clock was carried out by the use of the astronomical time scale ephemeris time (ET). This led to the internationally agreed definition of the latest SI second being based on atomic time.

Brau, Jean- Louis, Weaver, Helen, and Edwards, Allan, Larousse Encyclopedia of Astrology, New York: New American Library, 1982. Raphael’s Ephemeris was issued as a separate publication after Smith’s death, whilst others adopted and continued with the name ‘Raphael’. The "second Raphael" was John Palmer (1807–1837), a former student of Smith’s, who edited Raphael's Sanctuary of the Astral Art in 1834; the third was a Mr. Medhurst, the editor of the Prophetic Messenger between c. 1837–1847. Smith is sometimes confused with ‘Edwin Raphael’, who in fact was the pseudonym for the succeeding Raphael, (number four) a certain Mr. Wakeley (d. 1852). Number five was a Mr. Sparkes (1820–1875), editor of the Prophetic Messenger from 1852 to 1872, who even briefly edited Raphael’s Ephemeris’ main rival at the time, Zadkiel’s Almanac. (‘Zadkiel’ was the pseudonym of Richard James Morrison, an astrologer/inventor whose almanac dates back to 1831.)Papon, Donald, The Lure of the Heavens - A History of Astrology, Samuel Weiser, 1980.

Megaclite , also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000, and given the temporary designation '.IAUC 7555: Satellites of Jupiter 2001 January 5 (discovery)MPEC 2001-A29: S/2000 J 7, S/2000 J 8, S/2000 J 9, S/2000 J 10, S/2000 J 11 2001 January 15 (discovery and ephemeris)MPEC 2001-T59: S/2000 J 8, S/2000 J 9, S/2000 J 10 2001 October 15 (revised ephemeris) Megaclite is about 6 kilometres in diameter, and orbits Jupiter at an average distance of 24,687,000 kilometers in 792.437 days, at an inclination of 150° to the ecliptic (148° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.308. It was named in October 2002 after Megaclite, mother by Zeus (Jupiter) of Thebe and Locrus in Greek mythology.

Nevil Maskelyne, the newly appointed Astronomer Royal who was on the Board of Longitude, started with Mayer's tables and after his own experiments at sea trying out the lunar distance method, proposed annual publication of pre-calculated lunar distance predictions in an official nautical almanac for the purpose of finding longitude at sea. Being very enthusiastic for the lunar distance method, Maskelyne and his team of computers worked feverishly through the year 1766, preparing tables for the new Nautical Almanac and Astronomical Ephemeris. Published first with data for the year 1767, it included daily tables of the positions of the Sun, Moon, and planets and other astronomical data, as well as tables of lunar distances giving the distance of the Moon from the Sun and nine stars suitable for lunar observations (ten stars for the first few years).The Nautical Almanac and Astronomical Ephemeris, for the year 1767 This publication later became the standard almanac for mariners worldwide.

But the results varied throughout the year, which required corrections. To this the Portuguese used the astronomical tables (Ephemeris), precious tools for oceanic navigation, which have experienced a remarkable diffusion in the fifteenth century. These tables revolutionized navigation, allowing to calculate latitude. The tables of the Almanach Perpetuum, by astronomer Abraham Zacuto, published in Leiria in 1496, were used along with its improved astrolabe, by Vasco da Gama and Pedro Álvares Cabral.

It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003.MPEC 2003-E11: S/2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 March 4, 2003 (discovery and ephemeris) The moon was lost following its discovery in 2003. It was recovered in 2017 and given its permanent designation that year.

'Philophrosyne ( or ), also Jupiter LVIII and provisionally known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al. in 2003,IAUC 8116: Satellites of Jupiter and Saturn 2003 April (discovery)MPEC 2003-G17: S/2003 J 15 2003 April (discovery and ephemeris) but then lost. It was recovered in 2017 and given its permanent designation that year.

The first SSP was led by Dr. Paul Routly and Dr. Foster Strong. In 1960, Dr. George Abell joined the program for his first of more than 20 summers at SSP. The first year, SSP had 26 students. The students used data from the "Russian ephemeris" (Ephemyeredi Mahlikh Planyet) to find asteroids to photograph, measured the positions, and submitted the data to the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics.

The students were excited to find that when they calculated the orbit of 9 Metis, their data resulted in a significant correction to the Russian ephemeris. Women were admitted starting in 1969, and reached 50% of enrollment in 2010. After 41 summers at Thacher, a significant threat to the continuation of SSP came in 2000, when Thacher School decided to use its entire campus for a different purpose. SSP alumni incorporated Summer Science Program, Inc.

Huygenss distance from Titan Huygens trajectory from 25 December 2004 to 14 January 2005 All times given after 2005-Jan-14 09:11 UTC are expected event times and may differ from actual event times. This page will be updated after descent has occurred with corrections if they are necessary. The data used in this section has been slightly out of date, an updated version of ephemeris from ESA was available 2005 January 6.

The European GNSS Service Centre is the point of contact for Galileo users' assistance. The European GNSS Service Centre (GSC), located in Madrid, is an integral part of Galileo and provides the single interface between the Galileo system and Galileo users. GSC publishes Galileo official documentation, promotes Galileo current and future services worldwide, supports standardisation and distributes Galileo almanacs, ephemeris and metadata. The GSC User Helpdesk is the point of contact for Galileo user's assistance.

But the results varied throughout the year, which required corrections. To this the Portuguese used the astronomical tables (Ephemeris), precious tools for oceanic navigation, which have experienced a remarkable diffusion in the fifteenth century. These tables revolutionized navigation, allowing to calculate latitude. The tables of the Almanach Perpetuum, by astronomer Abraham Zacuto, published in Leiria in 1496, were used along with its improved astrolabe, by Vasco da Gama and Pedro Álvares Cabral.

The Boston Ephemeris was an almanac written by Mather in 1686. The content was similar to what is known today as the Farmer's Almanac. This was particularly important because it shows that Cotton Mather had influence in mathematics during the time of Puritan New England. This almanac contained a significant amount of astronomy, celestial within the text of the almanac the positions and motions of these celestial bodies, which he must have calculated by hand.

Further adjustments to Brown's theory were then made, arising from improved observational values of the fundamental astronomical constants used in the theory, and from re-working Brown's original analytical expansions to gain more precise versions of the coefficients used in the theory. Eventually, in 1984, Brown's work was replaced by results gained from more modern observational data (including data from lunar laser ranging) and altogether new computational methods for calculating the Moon's ephemeris.

Booker's Almanack did, he therefore wrote, # > Booker rebuked ; or, Animadversions on Booker's Teiescopium Uranicum or > Ephemeris, 1665, which is very erroneous, &c.; London, 1665, quarto, in one > sheet, which made much sport among people, having had the assistance therein > of Jo. Sargeant and Jo. Austen. # A Law Dictionary, interpreting such > difficult and obscure Words and Terms as are found either in our Common or > Statute, antient or modern Laws. London, 1671, fol.

Animation showing the alt=Io, Europa, and Ganymede move counter-clockwise along three concentric circles around Jupiter. Every time Europa reaches the top of its orbit, Io goes around twice in its orbit. Every time Ganymede reaches the top of its orbit, Io goes around four times in its orbit. During the 17th and 18th centuries astronomers used the ephemeris tables generated by Cassini to better understand the nature of the Jovian system and light.

Shortly afterwards, on 22 August 1784, he was placed under police surveillance, and his written work was subjected to censorship for the first time. He made one more attempt to launch a political journal with a more popular appeal, this time under the title "Vienna Ephemeris". This fared better than his earlier attempt, and was published till 1787, the year in which he left Vienna. Gemmingen's departure from Vienna was sudden and largely unexplained.

Also, the tables did not account for the effects of general relativity which was unknown at the time. Nevertheless, his tabulated values remain accurate to within a few seconds of arc to this day. He developed similar formulas and tables for the planets Mercury,"Tables of the Heliocentric Motion of Mercury", in: Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac, volume VI (1898), pp. 171-270 [Part II].

Shul and O'Grady 1994 Its "blue light" source star tracker, which could see stars during both day and night, would continuously track a variety of stars as the aircraft's changing position brought them into view. The system's digital computer ephemeris contained data on a list of stars used for celestial navigation: the list first included 56 stars, and was later expanded to 61."SR-71A-1 Flight Manual, Section IV, p. 3." sr-71.org.

Jupiter was worshipped also under the epithets of Imperator Maximus in Praeneste, Maius in Tusculum,Macrobius I 12, 17 who connects him to Roman Maia; CIL XIV 216; Ephemeris Epigraphica VII 1276. Praestes in Tibur,CIL 3555; cf. Historia Augusta Maximinus et Balbinus V 3; in Rome Iuppiter Praestitus CIL III 4037, Iuppiter praestabilis CIL IX 1498 and the Lares praestitites. Indiges at LaviniumLivy I 2, 6; Pliny NH III 56; Servius Aen.

The purpose of this institution was the refreshing trainings the young archaeologists and historians; also in this institution he initiated and led the publication of the yearbooks "Ephemeris Dacoromana" and "Diplomatarium Italicum", as well as the first series of the magazine "Dacia". He contributed to the formation of the historians Hortensia Dumitrescu, Vladimir Dumitrescu, Ecaterina Dunăreanu Vulpe, Ion Nestor, Dionisie M. Pippidi, Dorin Popescu, Gheorghe Ștefan, Radu Vulpe, who continued his activity.

The astronomers approached Dr. Gillies and Dr Jim Snyder to program the ILLIAC I computer to calculate the satellite orbit from this data. The programming and calculation was completed in under two days. The very rapid publication of the ephemeris (orbit) in the journal NatureI. R. King, G. C. McVittie, G. W. Swenson, Jr., and S. P. Wyatt, Jr., "Further observations of the first satellite," Nature, No. 4593, November 9, 1957, p. 943.

The new NSSCC building was equipped with an IBM 709 and, a few months later, with an IBM 7090. Major programming of the new computers was done by the Aeronutronic Division of the Ford Motor Company, Newport Beach CA. The Wolf Corporation also supported the NSSCC. The ephemeris computations were issued in what was called a bulletin. The bulletin listed each equatorial crossing of the satellite and described the path between crossings.

William of Saint-Cloud is a French astronomer in the late thirteenth century. He is known for his Almanac prepared around 1292, dedicated to Marie of Brabant, and translated for Joan of Navarre. This almanac, one of the rare witness of astronomical observations at the end of the High Middle Ages, contains ephemeris of the sun, moon and planets and advocates also the use of the camera obscura to observe solar eclipses.

Scylla (minor planet designation: 155 Scylla) is a main belt asteroid. It was discovered by Austrian astronomer Johann Palisa at the Austrian Naval Observatory on 8 November 1875, and named after the monster Scylla in Greek mythology. Two weeks after its discovery this asteroid became lost and was not recovered for 95 years. It was finally found by Paul Wild of Berne, Switzerland with the aid of an ephemeris created in 1970 by Conrad M. Bardwell at Cincinnati Observatory.

According to various Ephemeris, Solar, Lunar and Planetary, compiled and edited by eminent Foreign and Indian Chronologists like John Warren (1825), James Princep (1831), Robert Swell (1881). Hermann Jacobi (1888), L. D. Swemikennu Pillai (1911), V.B. Ketkar (1923), Gahlot and Devra for the years B.C.1 to 2000 A.D., on Vaishakh Shukla 11, Monday appears only during 1530 whereas in 1559 the day was Thursday. Zauhar Aftabchi, the Royal Diarist and Courtier of Humayun support this.

On 15 May 2018, 22:05 UT, the asteroid approached Earth at just over 0.5 LD, the closest approach of this asteroid in nearly 300 years. It was expected to reach apparent magnitude +11 at closest approach, bright enough to be seen in a small telescope if you have a custom ephemeris for your location. At closest approach, it was best seen from the Southern hemisphere such as South Africa and southern South America. The asteroid passed Earth going .

She wrote an article in which she gave a map of the eclipse's extent in 15-minute intervals across Europe and predicted the time and percentage each are in Europe would experience. The article was published in Connaissance des Temps (Knowledge of the times). She also created a group of catalogs of the stars which were useful for the future of astronomy. She calculated the ephemeris of the Sun, the Moon and the planets for the years 1774–1784.

Other newer satellites still transmit on this frequency. The downlink contains current date and time, Argos System satellite ephemeris data, and the downlink portion of the newer two-way communication link. Data collected from the Argos System is transmitted to the ground using two possible methods. If an Argos System ground receiving station is in view of the satellite while the transmitter is also in view, the data is transmitted and processed in near real time.

A Spaniard, Diego Mendez, and some natives paddled a canoe to get help from Hispaniola. The island's governor, Nicolás de Ovando y Cáceres, detested Columbus and obstructed all efforts to rescue him and his men. In the meantime, Columbus allegedly mesmerized the natives by correctly predicting a lunar eclipse for February 29, 1504, using the Ephemeris of the German astronomer Regiomontanus.Samuel Eliot Morison, Admiral of the Ocean Sea: A Life of Christopher Columbus, 1942, pp. 653–54.

Bedini, 1972, pp. 172—173. Banneker's Pennsylvania, Delaware, Maryland and Virginia Almanack and Ephemeris, for the Year of our Lord, 1792 was the first in a six-year series of almanacs and ephemerides that printers agreed to publish and sell. At least 28 editions of the almanacs, some of which appeared during the same year, were printed in seven cities in five states: Baltimore; Philadelphia; Wilmington, Delaware; Alexandria, Virginia; Petersburg, Virginia; Richmond, Virginia; and Trenton, New Jersey.

However, he eventually concluded that Newcomb was right, and not only was the Earth's rate of rotation slowing, but also there were random, unpredictable fluctuations, and he published these findings in a paper in 1926. Later work has shown this to be true, and astronomers now make a distinction between Universal Time, which is based on the Earth's rotation, and Terrestrial Time (formerly Ephemeris time), which is a uniform measure of the passage of time (see also ΔT).

Graph showing the difference DUT1 between UT1 and UTC (in seconds). Vertical segments correspond to leap seconds. Earth's rotational speed is very slowly decreasing because of tidal deceleration; this increases the length of the mean solar day. The length of the SI second was calibrated on the basis of the second of ephemeris time and can now be seen to have a relationship with the mean solar day observed between 1750 and 1892, analysed by Simon Newcomb.

DE408See at NASA's Navigation and Ancillary Information Facility website and which states that DE408 covered 20,000 years. was an unreleased ephemeris, created in 2005 as a longer version of DE406, covering 20,000 years. DE409 was released in 2003 for the MER spacecraft arrival at Mars and the Cassini arrival at Saturn. Further spacecraft ranging and VLBI (to the Mars Global Surveyor, Mars Pathfinder and the Mars Odyssey spacecraft) and telescopic data were included in the fit.

Almanacs contain some handwritten notes left by their readers. The value of the book can then be influenced upward or downward depending on the quality and content of these notes, and especially the person who wrote them - when you can identify it. They are usually found on page intentionally left blank for the ephemeris. Some of these notes can provide very interesting information, such as notes written on the page in August 1715 a copy of the BNF.

A Java applet is available and provided as a 3D orbit visualization tool. The applet was implemented using unreliable 2-body methods, and hence should not be used for determining accurate long- term trajectories (over several years or decades) or planetary encounter circumstances. For accurate ephemerides use the JPL Horizons On-Line Ephemeris System that handles the n-body problem using numerical integration. The Java applet is available by adding ";orb=1" to the end of the body's URL.

Geminga underwent a minor glitch in the late part of 1996, with a fractional change in frequency of 6.2 × 10−10. A 1998 study of the pre-glitch ephemeris suggested that the timings were being affected by reflex motion due to the presence of a low-mass planet in a 5.1-year orbit, however this was later shown to be an artifact of noise that affects the pulse times from Geminga rather than a genuine orbital effect.

For example, the Astronomical Almanac uses TT for its tables of positions (ephemerides) of the Sun, Moon and planets as seen from Earth. In this role, TT continues Terrestrial Dynamical Time (TDT or TD),TT is equivalent to TDT, see IAU conference 1991, Resolution A4, recommendation IV, note 4. which in turn succeeded ephemeris time (ET). TT shares the original purpose for which ET was designed, to be free of the irregularities in the rotation of Earth.

These times can be calculated based on known satellite ephemeris information and approximate transmitter location, and can therefore be avoided when taking FDOA measurements. The process of geolocating a signal requires some knowledge of the signal and all the techniques in order to get an accurate location. The geolocation of a CW signal is nearly impossible with TDOA-FDOA. Nevertheless, a nominally CW transmission can contain imperfections, especially if a station transmits near its maximum EIRP.

TDB is a successor of Ephemeris Time (ET), in that ET can be seen (within the limits of the lesser accuracy and precision achievable in its time) to be an approximation to TDB as well as to Terrestrial Time (TT) (see Ephemeris time § Implementations). TDB in the form of the very closely analogous, and practically equivalent, time scale Teph continues to be used for the important DE405 planetary and lunar ephemerides from the Jet Propulsion Laboratory. Arguments have been put forward for the continued practical use of TDB rather than TCB based on the very small size of the difference between TDB and TT, not exceeding 0.002 second, which can be neglected for many applications. It has been argued that the smallness of this difference makes for a lower risk of damage if TDB is ever confused with TT, compared to the possible damage of confusing TCB and TT, which have a relative linear drift of about 0.5 second per year,S A Klioner (2008), "Relativistic scaling of astronomical quantities and the system of astronomical units", Astronomy and Astrophysics, vol.

Funded by NASA, the NASA Exoplanet Archive serves the user community working with exoplanet data, primarily by serving transit data sets from Kepler mission and COnvection ROtation and planetary Transits (CoRoT) and providing long-term data curation and analysis tools. The archive content includes exoplanet and stellar host properties and Kepler candidate properties in interactive tables and time series data from space- and ground-based projects. Analysis tools include visualizations, periodogram calculations, and transit ephemeris predictions. The new service is available at exoplanetarchive.ipac.caltech.edu.

Astronomical Papers of the American Ephemeris (1943) Clemence identified systematic errors in the predictions of Mars' path. The residuals showed a marked periodicity and Clemence concluded that the Fourier series on which the predictions were based was wrong. Clemence set out to derive a new series from scratch using the methods detailed by Hill and Peter Andreas Hansen in the nineteenth century. The calculations were carried out with "a lead pencil, large sheets of computing paper, [and] a hand- operated Millionaire desk calculator".

It was also used to time astronomical events by users of the American Ephemeris and Nautical Almanac, first published for the year 1855. In 1897, well after the Old Naval Observatory closed in 1892, the Coast and Geodetic Survey reported that its meridian was 77°3′2.3″ west of Greenwich,3618 Serial Set 254 which was quoted for the next 50 years in the list of observatories in the Almanac as . This old Washington meridian was repealed on 22 August 1912.37 Stat.

The relative accuracy is likewise improved, to about 2.5 cm. Even if the StarFire correction signal is lost for more than 20 minutes, the internal ionospheric corrections alone result in accuracy of about 3 m. StarFire receivers also receive WAAS signals, ignoring their ionospheric data and using their (less detailed) ephemeris and clock adjustment data to provide about 50 cm accuracy. In comparison, "normal" GPS receivers generally offer about 15 m accuracy, and ones using WAAS improve this to about 3 m.

Herget taught astronomy at the University of Cincinnati. He was a pioneer in the use of machine methods, and eventually digital computers, in the solving of scientific and specifically astronomical problems (for example, in the calculation of ephemeris tables for minor planets). During World War II he applied these same talents to the war effort, helping to locate U-boats by means of the application of spherical trigonometry. Herget established the Minor Planet Center at the university after the war in 1947.

One of the major problems in trajectory and orbital estimation is to obtain a realistic estimate of the accuracy of the trajectory and other important parameters. In the orbital case, some of the parameters which may not be solved for are geopotential constants, survey, etc. These factors will affect the total uncertainty in the orbit and, of course, ephemeris predictions. A statistical technique was developed that performs a variance-covariance propagation to obtain accuracy estimates based on random and unmodeled errors.

Meanwhile, Dominique, visits her late dad who died, and her mother, is often absent, working to pay the bills. Shortly, Heather's legs are broken by two cars in an apparent freak accident. Guiltless, Ursula attempts to prove the authenticity of the book to a skeptical Dominique, targeting Heather's boyfriend, Kyle, whose face becomes burned and blistered by a corrosive liquid upon falling down during a Chemistry class exam. Ursula grows pale and diabolical, and the book previously untitled now reads Ephemeris Diaboli.

In an ephemeris, the position angle of the midpoint of the bright limb of the Moon or planets, and the position angles of their North poles may be tabulated. If this angle is measured from the North point on the limb, it can be converted to an angle measured from the zenith point (the vertex) as seen by an observer by subtracting the parallactic angle. The position angle of the bright limb is directly related to that of the subsolar point.

Donald B. Gillies and Jim Snyder programmed the ILLIAC I computer to calculate the satellite orbit from this data. The programming and calculation was completed in less than two days. The rapid publication of the ephemeris (orbit) in the journal Nature within a month of the satellite launch helped to dispel some of the fears created by the Sputnik launch. It also lent credence to the spurious idea that the Sputnik launch was part of an organized effort to dominate space.

The Besselian year is a tropical year that starts when the (fictitious) mean Sun reaches an ecliptic longitude of 280°. This is currently on or close to January 1. It is named after the 19th-century German astronomer and mathematician Friedrich Bessel. The following equation can be used to compute the current Besselian epoch (in years): : B = 1900.0 + (Julian dateTT − ) / The TT subscript indicates that for this formula, the Julian date should use the Terrestrial Time scale, or its predecessor, ephemeris time.

Geolocation on highly inclined satellites, either one of both being used in the measurement, will result in more accurate results by performing FDOA – FDOA geolocation. This is due to a large difference in relative motion, leading to a large difference in relative frequency between the two satellites. A related point is the error to FDOA-FDOA calculation contributed by ephemeris uncertainty is relatively small. Moving targets are not likely to be located using FDOA methods, unless using a highly inclined satellite.

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.

Sir John Strode's widow, Lady Ann, was struck dead by a Parliamentarian soldier while defending her home during the Civil War. Strode made copious annotations to an almanack "An Ephemeris for the Year 1652" by Nicholas Culpeper in which he fiercely attacked the Parnham Strodes. Later ramblings suggest that Strode had become mentally unstable and he was imprisoned in the Fleet prison with debts of £200. He wrote long letters to Oliver Cromwell setting out his grievances and he was eventually released as being of unsound mind.

He next collected observations of the positions of the planets as far back as 1750. Examining these and correcting for inconsistencies with the most recent data occupied him until 1852. Le Verrier published, in the Annales de l'Observatoire de Paris, tables of the motions of all of the known planets, releasing them as he completed them, starting in 1858.see, for instance, The tables formed the fundamental ephemeris of the Connaissance des Temps, the astronomical almanac of the Bureau des Longitudes, until about 1912.

Covers late 1899 through 2049. DE402 was released in 1995, and was quickly superseded by DE403. DE403 was created 1993, released in 1995, expressed in the coordinates of the International Earth Rotation Service (IERS) reference frame, essentially the ICRF. The data compiled by JPL to derive the ephemeris began to move away from limited-accuracy telescopic observations and more toward higher-accuracy radar-ranging of the planets, radio-ranging of spacecraft, and very-long-baseline-interferometric (VLBI) observations of spacecraft, especially for the four inner planets.

On May 6, 2004 the comet approached within 0.32 AU of the Earth. Beginning in early May, the comet started racing north and burst into view in the northern hemisphere when it had reached almost maximum brightness. With a near perihelion orbital eccentricity of 1.00069 (epoch 2004-May-18) that keeps a barycentric epoch 2014-Jan-01 eccentricity of 1.00067, (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0) this hyperbolic comet is going to be ejected from the Solar System.

In the meantime, Columbus had to mesmerize the natives in order to prevent being attacked by them and gain their goodwill. He did so by correctly predicting a lunar eclipse for February 29, 1504, using the Ephemeris of the German astronomer Regiomontanus.Morison, Samuel Eliot, Christopher Columbus, Mariner, 1955, pp. 184–192. In May 1504 a battle took place between men loyal to Columbus and those loyal to the Porras brothers, in which there was a sword fight between Bartolomé Colón and Francisco de Porras.

The Astronomical AlmanacThe Astronomical Almanac for the Year 2015, (United States Naval Observatory/Nautical Almanac Office, 2014) . is an almanac published by the United States Naval Observatory (USNO) and Her Majesty's Nautical Almanac Office (HMNAO); it also includes data supplied by many scientists from around the world. It is considered a worldwide resource for fundamental astronomical data, often being the first publication to incorporate new International Astronomical Union resolutions. The almanac largely contains solar system ephemeris and catalogs of selected stellar and extragalactic objects.

At the local meridian the Sun reaches its highest point on its daily arc across the sky. In 1874 the British Association for the Advancement of Science introduced the CGS (centimetre/gramme/second system) combining fundamental units of length, mass and time. The second is "elastic", because tidal friction is slowing the earth's rotation rate. For use in calculating ephemerides of celestial motion, therefore, in 1952 astronomers introduced the "ephemeris second", currently defined as The CGS system has been superseded by the Système international.

In 1935, she had discovered that a report she had been given to translate into English, made by Nikolai Mikhailovich, Voronov contained errors in its calculations. Voronov was a rising star and had published a paper on the theories of the motion of small planets. He was offered a position at the Pulkovo Observatory on the basis of that paper and produced another, calculating the ephemeris of 13 Egeria. It was in this paper that Gaze found the error and reported it to her superior.

In 2008 Engel introduced light pre-pass rendering as a method of deferred shading variant in the development of videogame graphics, and is known as an expert in shader programming. Engel then founded Confetti Interactive and Confetti Games in 2009, where he serves as CEO. Confetti is a think-tank for real-time graphics research in the videogame and movie industry, graphics tools developer, and programming services company. Tools Engel has helped develop for the company include Aura, a global illumination system; Ephemeris, a skybox/skydome system; and PixelPuzzle, a Post FX pipeline system.

In 2000, an executive order by President Bill Clinton turned it off permanently in 2000. Nevertheless, by this point DGPS had evolved into a system for providing more accuracy than even a non-SA GPS signal could provide on its own. There are several other sources of error which share the same characteristics as SA in that they are the same over large areas and for "reasonable" amounts of time. These include the ionospheric effects mentioned earlier, as well as errors in the satellite position ephemeris data and clock drift on the satellites.

DGPS Reference Station (choke ring antenna) A reference station calculates differential corrections for its own location and time. Users may be up to 200 nautical miles (370 km) from the station, however, and some of the compensated errors vary with space: specifically, satellite ephemeris errors and those introduced by ionospheric and tropospheric distortions. For this reason, the accuracy of DGPS decreases with distance from the reference station. The problem can be aggravated if the user and the station lack "inter visibility"—when they are unable to see the same satellites.

Ephemeris by Abraham Zacuto in Almanach Perpetuum, 1496 In the thirteenth century celestial navigation was already known, guided by the sun position. For celestial navigation the Portuguese, like other Europeans, used Arab navigation tools, like the astrolabe and quadrant, which they made easier and simpler. They also created the cross-staff, or cane of Jacob, for measuring at sea the height of the sun and other stars. The Southern Cross become a reference upon arrival at the Southern hemisphere by João de Santarém and Pedro Escobar in 1471, starting the celestial navigation on this constellation.

'Eirene , also Jupiter LVII and originally known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003.IAUC 8087: Satellites of Jupiter 2003 March 4 (discovery)MPEC 2003-E11: S/2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 2003 March 4 (discovery and ephemeris) but was then lost. It was recovered in 2017 and given its permanent designation that year.

'Jupiter LXI, provisionally known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers led by Brett J. Gladman, et al. in 2003.IAUC 8125: S/2003 J 19 and S/2003 J 20 2003 April (discovery)MPEC 2003-G64: S/2003 J 19 2003 April (discovery and ephemeris) is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 22,709 Mm in 699.125 days, at an inclination of 165° to the ecliptic (164° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.1961.

50ffKourouniotes, K. (1904) Archaiologike Ephemeris, 153ff.Kourouniotes, K. (1909) Praktika, pp. 185–200 The Mt. Lykaion Excavation and Survey Project, a joint effort of the University of Pennsylvania and the University of Arizona began work at the site in 2004, with the aim of continuing the topographical survey begun in 1996 and carrying out a full topographical and architectural analysis not only of the altar and temenos, but of the nearby valley where the Lykaian Games were held. The detailed digital records and drawings of every architectural stone block.

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.

Although it was less accurate than existing quartz clocks, it served to demonstrate the concept. The first accurate atomic clock, a caesium standard based on a certain transition of the caesium-133 atom, was built by Louis Essen in 1955 at the National Physical Laboratory in the UK. Calibration of the caesium standard atomic clock was carried out by the use of the astronomical time scale ephemeris time (ET). As of 2013, the most stable atomic clocks are ytterbium clocks, which are stable to within less than two parts in 1 quintillion ().

Ephemeris by Abraham Zacuto in Almanach Perpetuum, 1496 In the thirteenth century celestial navigation was already known, guided by the sun position. For celestial navigation the Portuguese, like other Europeans, used Arab navigation tools, like the astrolabe and quadrant, which they made easier and simpler. They also created the cross-staff, or cane of Jacob, for measuring at sea the height of the sun and other stars. The Southern Cross become a reference upon arrival at the Southern hemisphere by João de Santarém and Pedro Escobar in 1471, starting the celestial navigation on this constellation.

A fundamental ephemeris of the Solar System is a model of the objects of the system in space, with all of their positions and motions accurately represented. It is intended to be a high-precision primary reference for prediction and observation of those positions and motions, and which provides a basis for further refinement of the model. It is generally not intended to cover the entire life of the Solar System; usually a short-duration time span, perhaps a few centuries, is represented to high accuracy. Some long ephemerides cover several millennia to medium accuracy.

Within the limits of observable accuracy, ephemeris seconds are of constant length, as are atomic seconds. This publication allowed a value to be chosen for the length of the atomic second that would accord with the celestial laws of motion. In 1961, the Bureau International de l'Heure began coordinating the UTC process internationally (but the name Coordinated Universal Time was not formally adopted by the International Astronomical Union until 1967). From then on, there were time steps every few months, and frequency changes at the end of each year.

Shortly after its initial discovery it was found to have an orbital period of about 70 years with an error of about 5 years. Johann Franz Encke determined a definitive orbit with a period of 70.68 years. This orbit was used to generate an ephemeris for the 1883-4 return, but searches were unsuccessful, until it was rediscovered by Brooks. This year it traveled from Scheat and Markab in western Pegasus, 13 January 1884; southward (through Pisces) to reach perihelion below Iota and Beta Ceti (~RA 0h, Dec.

Though the masses had not yet been adopted by the IAU. The ephemerides were created to support the arrivals of the MER and Cassini spacecraft. DE411See, for instance, which compares DE413 output with DE411. was widely cited in the astronomical community, but not publicly released by JPL DE412See, for instance, which references DE412. was widely cited in the astronomical community, but not publicly released by JPL DE413 was released in 2004 with updated ephemeris of Pluto in support of the occultation of a star by its satellite Charon on 11 Jul 2005.

Indeed, the emperor Tiberius had had his destiny predicted for him at birth, and so surrounded himself with astrologers such as Thrasyllus of Mendes. According to Juvenal 'there are people who cannot appear in public, dine or bathe, without having first consulted an ephemeris'. Claudius, on the other hand favoured augury and banned astrologers from Rome altogether. It is perhaps not surprising, that in the course of time, to be known as a "Chaldaean" carried with it frequently the suspicion of charlatanry and of more or less willful deception.

In theory the GPS signal with Selective Availability turned off offers accuracy on the order of 3 m. In practice, typical accuracy is about 15 m. Of this 12 m, about 5 m is due to distortion from "billows" in the ionosphere, which introduce propagation delays that makes the satellite appear farther away than it really is. Another 3 to 4 m is accounted for by errors in the satellite ephemeris data, which is used to calculate the positions of the GPS satellites, and by clock drift in the satellite's internal atomic clocks.

By 1956 it had gained more computing power than all computers in Bell Labs combined. Data was represented in 40-bit words, of which 1,024 could be stored in the main memory, and 12,800 on drum memory. Immediately after the 1957 launch of Sputnik, the ILLIAC I was used to calculate an ephemeris of the satellite's orbit, later published in Nature.I. R. King, G. C. McVittie, G. W. Swenson, Jr., and S. P. Wyatt, Jr., "Further observations of the first satellite", Nature, No. 4593, 1957 November 9, p.

Before the August fading of the comet, the Minor Planet Center ephemeris projected that the originally bright comet Elenin would reach about 6th magnitude in September and October 2011, (C/2010 X1) but the brightness depends on the activity level of the coma. But because Elenin disintegrated, it did not become visible to the naked eye or binoculars. Elenin made its closest apparent pass in the night sky to Comet 45P/Honda–Mrkos–Pajdušáková on the morning of October 8, and moved apparently close to Mars on October 15.

175 Andromache (minor planet designation: 175 Andromache) is a main-belt asteroid that was discovered by Canadian-American astronomer J. C. Watson on October 1, 1877, and named after Andromache, wife of Hector during the Trojan War. Watson's telegram to Europe announcing the discovery became lost, and so notification did not arrive until several weeks later. As a result, another minor planet, later designated 176 Iduna, was initially assigned the number 175. The initial orbital elements for 175 Andromache proved unreliable, and it was only in 1893 that an accurate ephemeris was produced.

Marsden responded that the delay was unfortunate, and that Boethin should try to cable future reports instead of sending letters, which could take weeks to arrive from the remote Abra province. Marsden was not optimistic that the comet could be recovered. Defying the odds, Boethin was able to observe his comet again in late January and early February, and he sent a telegram to the Central Bureau for Astronomical Telegrams. Using the new report, Marsden was able to calculate an ephemeris for the comet, and it was quickly confirmed by other observers.

Ephemeris time (ET), adopted as standard in 1952, was originally designed as an approach to a uniform time scale, to be freed from the effects of irregularity in the rotation of the earth, "for the convenience of astronomers and other scientists", for example for use in ephemerides of the Sun (as observed from the Earth), the Moon, and the planets. It was proposed in 1948 by G M Clemence.G M Clemence (1948). From the time of John Flamsteed (1646–1719) it had been believed that the Earth's daily rotation was uniform.

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).

B Guinot & P K Seidelmann (1988), at p.305. Reasons for the use of lunar measurements were practically based: the Moon moves against the background of stars about 13 times as fast as the Sun's corresponding rate of motion, and the accuracy of time determinations from lunar measurements is correspondingly greater. When ephemeris time was first adopted, time scales were still based on astronomical observation, as they always had been. The accuracy was limited by the accuracy of optical observation, and corrections of clocks and time signals were published in arrear.

According to the astrologer Neil Michelsen's "The American Ephemeris," on 24 August 1987 there was an exceptional alignment of planets in the Solar System. Eight planets were aligned in an unusual configuration called a grand trine. The Sun, Moon and six out of eight planets formed part of the grand trine, that is, they were aligned at the apexes of an equilateral triangle when viewed from the Earth. The Sun, Moon, Mars and Venus were in exact alignment, astrologically called a conjunction at the first degree of Virgo in Tropical Astrology.

Ijiraq, or Saturn XXII (22), is a small prograde irregular satellite of Saturn. It was discovered by the team of Brett Gladman, John J. Kavelaars, et al. in 2000, and given the temporary designation '.IAUC 7521: S/2000 S 5, S/2000 S 6 November 18, 2000 (discovery)MPEC 2000-Y14: S/2000 S 3, S/2000 S 4, S/2000 S 5, S/2000 S 6, S/2000 S 10 December 19, 2000 (discovery and ephemeris) It was named in 2003 after the ijiraq, a creature in Inuit mythology.

OSSOS observed eight blocks of the sky over a period of five years from 2013–2017 using the MegaPrime camera of the 3.6 m Canada-France-Hawaii Telescope. Images of these blocks were taken near opposition (when the block is near opposite the sun), two months before, and two months after. This extended period of observation was designed to remove ephemeris bias which can cause the loss of some objects due to inaccurate predictions of their future positions. Pointing directions, detection efficiencies, and tracking frequencies were determined to allow other observational biases to be identified.

From 1846 to 1849, he worked in the United States Coast Survey on board the , where he discovered a previously unknown shoal that had caused shipwrecks off the coast of New York. During his service to the Survey, he was also responsible for researching tides and currents and acted as an inspector on a number of naval shipyards. From 1849 to 1855 he was the first superintendent of American Nautical Almanac Office and produced the American Ephemeris and Nautical Almanac. In 1854, he was promoted to Commander and given the command of the .

Among the slow correction data is the ionospheric delay. As the GPS signal travels from the satellite to the receiver, it passes through the ionosphere. The receiver calculates the location where the signal pierced the ionosphere and, if it has received an ionospheric delay value for that location, corrects for the error the ionosphere created. While the slow data can be updated every minute if necessary, ephemeris errors and ionosphere errors do not change this frequently, so they are only updated every two minutes and are considered valid for up to six minutes.

The Prutenic Tables ( from Prutenia meaning "Prussia", ), were an ephemeris (astronomical tables) by the astronomer Erasmus Reinhold published in 1551 (reprinted in 1562, 1571 & 1585). They are sometimes called the Prussian Tables after Albert I, Duke of Prussia, who supported Reinhold and financed the printing. Reinhold calculated this new set of astronomical tables based on Nicolaus Copernicus' De revolutionibus orbium coelestium, the epochal exposition of Copernican heliocentrism published in 1543. Throughout his explanatory canons, Reinhold used as his paradigm the position of Saturn at the birth of the Duke, on 17 May 1490.

E.R. Squibb & Son facility in Long Island City, New York, in 1948 The Squibb corporation was founded in 1858 by Edward Robinson Squibb in Brooklyn, New York. Squibb was known as an advocate of quality control and high purity standards early within the pharmaceutical industry. He went on to self-publish an alternative to the U.S. Pharmacopeia titled Squibb's Ephemeris of Materia Medica, after failing to convince the American Medical Association to incorporate higher purity standards. Materia Medica, Squibb products, and Edward Squibb's opinion on the fundamentals of pharmacy are found in many medical papers of the late 1800s.

The Earth's orbit, and the satellite's orbit with respect to the Earth, were essential for describing the location of the observer at each epoch of observation, and were supplied by an appropriate Earth ephemeris combined with accurate satellite ranging. Corrections due to special relativity (stellar aberration) made use of the corresponding satellite velocity. Modifications due to general relativistic light bending were significant (4 milliarc-sec at 90° to the ecliptic) and corrected for deterministically assuming γ=1 in the PPN formalism. Residuals were examined to establish limits on any deviations from this general relativistic value, and no significant discrepancies were found.

'Mneme , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al. in 2003, and was provisionally designated S/2003 J 21.IAUC 8138: S/2003 J 21 2003 May 30 (discovery)MPEC 2003-K45: S/2003 J 21 2003 May 29 (discovery and ephemeris) Mneme is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 21,427,000 kilometres in 640.769 days, at an inclination of 149° to the ecliptic (148° to Jupiter's equator) with an eccentricity of 0.2214.

' is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard et al. in 2004 from pictures taken in 2003.IAUC 8281: S/2003 J 23 2004 February 4 (discovery)MPEC 2004-B81: S/2003 J 23 2004 January 31 (discovery and ephemeris) is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 22,740 Mm in 700.538 days, at an inclination of 149° to the ecliptic (149° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.3931.

Earth's rotation period relative to the Sun (its mean solar day) consists of 86,400 seconds of mean solar time, by definition. Each of these seconds is slightly longer than an SI second because Earth's solar day is now slightly longer than it was during the 19th century, due to tidal deceleration. The mean solar second between 1750 and 1892 was chosen in 1895 by Simon Newcomb as the independent unit of time in his Tables of the Sun. These tables were used to calculate the world's ephemerides between 1900 and 1983, so this second became known as the ephemeris second.

The DASCH will not generally accept special requests for scanning a particular part of the sky from the collection so that the digitization progresses efficiently. The DASCH team did accommodate two special requests to image plates that were not part of the Harvard collection "for scientifically compelling reasons." The New Horizons team requested images of Pluto in order to improve the dwarf planet's ephemeris that was needed to plan precise adjustments to the spacecraft's trajectory. DASCH scanned 843 plates showing Pluto that were taken by the 40 inch telescope at Lowell Observatory from 1930 to 1951.

Authorized by Congress in 1849, the American Nautical Almanac Office was founded and attached to the Department of the Navy with Charles Henry Davis as the first superintendent. The American Ephemeris and Nautical Almanac was first published in 1852, containing data for the year 1855. Its data was originally calculated by human "computers", such as Chauncey Wright and Joseph Winlock. Between 1855 and 1881 it had two parts, the first for the meridian of Greenwich contained data on the Sun, Moon, lunar distances, Venus, Mars, Jupiter, and Saturn, which was published separately as The American Nautical Almanac.

Eves, Chapter 2. The ancient Babylonians had known of theorems concerning the ratios of the sides of similar triangles for many centuries, but they lacked the concept of an angle measure and consequently, studied the sides of triangles instead. The Babylonian astronomers kept detailed records of the rising and setting of stars, the motion of the planets, and the solar and lunar eclipses, all of which required familiarity with angular distances measured on the celestial sphere. They also used a form of Fourier analysis to compute ephemeris (tables of astronomical positions), which was discovered in the 1950s by Otto Neugebauer.

In September 1725 he was allowed to return to his province, with the exception of the city of Naples, where he could only reside since 1738. He taught Italian literature, moral theology, mathematics and astronomy at the Collegio del Salvatore and from 1740 at the Seminary of the Nobles. Gianpriamo published the treatise on astronomy Specula parthenopaea uranophilis juventibus excitata in 1748 for his pupils of the Neapolitan college. He reported the observations made in Europe, in China and in his travels by land and sea, calculating the ephemeris of stars and planets for the meridian of Naples.

Annual almanacs are published listing the derived values and methods of use. Until 1983, the Astronomical Almanac's angular value of the mean obliquity for any date was calculated based on the work of Newcomb, who analyzed positions of the planets until about 1895: : where is the obliquity and is tropical centuries from B1900.0 to the date in question. From 1984, the Jet Propulsion Laboratory's DE series of computer- generated ephemerides took over as the fundamental ephemeris of the Astronomical Almanac. Obliquity based on DE200, which analyzed observations from 1911 to 1979, was calculated: : where hereafter is Julian centuries from J2000.0.

Using JPL Horizons with an observed orbital arc of 271 days, the barycentric orbital elements for epoch 2500 generate a hyperbolic orbit with an eccentricity of 1.0004. (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0) (saved Horizons output file 2011-Aug-08) Before entering the planetary region (epoch 1600), Elenin had a calculated barycentric orbital period of tens of millions of years with an apoapsis (aphelion) distance of about . Elenin was probably in the outer Oort cloud with a loosely bound chaotic orbit that was easily perturbed by passing stars.

While serving in this position, he simultaneously pursued other scholarly interests such as releasing a calendar and ephemeris in 1552 as well as the subsequent year. Then in 1552, Rheticus was found guilty of raping the son of Hans Meusel, a merchant, though the exact nature of this encounter has been called into question. According to Meusel, Rheticus "plied him with a strong drink, until he was inebriated; and finally did with violence overcome him and practice upon him the shameful and cruel vice of sodomy". He fled following this accusation, for a time residing in Chemnitz before eventually moving on to Prague.

Being both an astronomer and an astrologer, he tried to base astrology on solid mathematical and astronomical ground. His first published work was "Tabulae eclipsum", predicting (within a few minutes) the start and the duration of lunar eclipses until 1605, including towns where it would be observable. These tables were based on the work of Erasmus Reinhold. In 1564, by order of Maximilian II, he published detailed ephemeris tables for the sun, moon and other celestial bodies covering the years 1564 - 1574 in 10-day intervals and titled "De coniunctionibus magnis insignoribus superiorum planetarum, solis defectibus, et de cometis effectum historica expositione".

With the definitions used before 2012, the astronomical unit was dependent on the heliocentric gravitational constant, that is the product of the gravitational constant, G, and the solar mass, . Neither G nor can be measured to high accuracy separately, but the value of their product is known very precisely from observing the relative positions of planets (Kepler's Third Law expressed in terms of Newtonian gravitation). Only the product is required to calculate planetary positions for an ephemeris, so ephemerides are calculated in astronomical units and not in SI units. The calculation of ephemerides also requires a consideration of the effects of general relativity.

The beginning of the «Ephemeris belli Troiani» ascribed to Dictys Cretensis in a manuscript of the Abbey of Saint Gall: St. Gallen, Stiftsbibliothek, Cod. Sang. 197, page 1 (late 9th century) Dictys Cretensis, i.e. Dictys of Crete (, ; ) of Knossus was a legendary companion of Idomeneus during the Trojan War, and the purported author of a diary of its events, that deployed some of the same materials worked up by Homer for the Iliad. The story of his journal, an amusing fiction addressed to a knowledgeable and sophisticated Alexandrian audience, came to be taken literally during Late Antiquity.

Although ephemeris time was defined in principle by the orbital motion of the Earth around the Sun,Clemence (1948), at pp.171-3. it was usually measured in practice by the orbital motion of the Moon around the Earth.W Markowitz & others (1955); W Markowitz (1959); also W Markowitz, R G Hall, L Essen, J V L Parry (1958). These measurements can be considered as secondary realizations (in a metrological sense) of the primary definition of ET in terms of the solar motion, after a calibration of the mean motion of the Moon with respect to the mean motion of the Sun.

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.

For scientific uses, a modern planetary ephemeris comprises software that generates positions of planets and often of their satellites, asteroids, or comets, at virtually any time desired by the user. Typically, such ephemerides cover several centuries, past and future; the future ones can be covered because the field of celestial mechanics has developed several accurate theories. Nevertheless, there are secular phenomena which cannot adequately be considered by ephemerides. The greatest uncertainties in the positions of planets are caused by the perturbations of numerous asteroids, most of whose masses and orbits are poorly known, rendering their effect uncertain.

Thyone , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al. in 2001, and given the temporary designation '.IAUC 7900: Satellites of Jupiter 2002 May 16 (discovery)MPEC 2002-J54: Eleven New Satellites of Jupiter 2002 May (discovery and ephemeris) Thyone is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 21,605,000 kilometres in 639.803 days, at an inclination of 147.28° to the ecliptic (146.93° to Jupiter's equator) with an eccentricity of 0.2526.

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.

Albiorix is a prograde irregular satellite of Saturn. It was discovered by Holman and colleagues in 2000, and given the temporary designation S/2000 S 11.IAUC 7545: S/2000 S 11 19 December 2000 (discovery)MPEC 2000-Y13: S/2000 S 11 19 December 2000 (discovery and ephemeris)Gladman, B. J.; Nicholson, P. D.; Burns, J. A.; Kavelaars, J. J.; Marsden, B. G.; Holman, M. J.; Grav, T.; Hergenrother, C. W.; Petit, J.-M.; Jacobson, R. A.; and Gray, W. J.; Discovery of 12 satellites of Saturn exhibiting orbital clustering, Nature, 412 (July 12, 2001), pp.

Praxidike , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000,IAUC 7555: Satellites of Jupiter January 5, 2001 (discovery)MPEC 2001-A29: S/2000 J 7, S/2000 J 8, S/2000 J 9, S/2000 J 10, S/2000 J 11 January 15, 2001 (discovery and ephemeris) and given the temporary designation '. It was named in August 2003 after Praxidice,IAUC 7998: Satellites of Jupiter 2002 October 22 (naming the moon) the Greek goddess of punishment.

Theoretically, this could have been observed by both Spirit and Opportunity; however, camera resolution did not permit seeing Mercury's 6.1" angular diameter. They were able to observe transits of Deimos across the Sun, but at 2' angular diameter, Deimos is about 20 times larger than Mercury's 6.1" angular diameter. Ephemeris data generated by JPL Horizons indicates that Opportunity would have been able to observe the transit from the start until local sunset at about 19:23 UTC Earth time, while Spirit would have been able to observe it from local sunrise at about 19:38 UTC until the end of the transit.

He realized that more accurate observations would be the key to making more exact predictions. He purchased an ephemeris and books on astronomy, including Johannes de Sacrobosco's De sphaera mundi, Petrus Apianus's Cosmographia seu descriptio totius orbis and Regiomontanus's De triangulis omnimodis. Jørgen Thygesen Brahe, however, wanted Tycho to educate himself in order to become a civil servant, and sent him on a study tour of Europe in early 1562. 15-year old Tycho was given as mentor the 19-year-old Anders Sørensen Vedel, whom he eventually talked into allowing the pursuit of astronomy during the tour.

Time coordinates on the TT and TCG scales are conventionally specified using traditional means of specifying days, carried over from non-uniform time standards based on the rotation of Earth. Specifically, both Julian Dates and the Gregorian calendar are used. For continuity with their predecessor Ephemeris Time (ET), TT and TCG were set to match ET at around Julian Date (1977-01-01T00Z). More precisely, it was defined that TT instant 1977-01-01T00:00:32.184 exactly and TCG instant 1977-01-01T00:00:32.184 exactly correspond to the International Atomic Time (TAI) instant 1977-01-01T00:00:00.000 exactly.

Eukelade , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003, and received the temporary designation '.IAUC 8087: Satellites of Jupiter 2003 March 4 (discovery)MPEC 2003-E11: S/2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 2003 March 4 (discovery and ephemeris)MPEC 2003-E29: S/2003 J 9, 2003 J 10, 2003 J 11, 2003 J 12; S/2003 J 1, 2003 J 6 2003 April 3 (revised ephemeris) Eukelade is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 23,484,000 km in 735.200 days, at an inclination of 164° to the ecliptic (165° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2829. It was named in March 2005 after Eucelade, described by some Greek writers as one of the Muses, and thus a daughter of Zeus (Jupiter).IAUC 8502: Satellites of Jupiter 2005 March 30 (naming the moon)Scholies d’Hésiode (in Greek and French, translation by Michel Tichit), EducNet MusAgora: Les Muses dans la littérature grecque ancienne Eukelade belongs to the Carme group, made up of irregular retrograde moons orbiting Jupiter at a distance ranging between 23 and 24 Gm and at an inclination of about 165°.

It began publication in 1776 and continued until 1960 when it was merged into the international edition of the Astronomical Ephemeris and Apparent Places of Fundamental Stars (APFS). This merger was decided in 1959 by the IAU. Starting in 1907 it contained accurate apparent places of the first international fundamental catalogue which was compiled for astrometry; later these data were actualized within the framework of the Catalogues of Fundamental Stars FK3 and FK4. In the 1940s the Almanac was edited in co-operation with the Astronomisch-Geodätisches Jahrbuch of the Recheninstitut in Heidelberg, Germany, which was also merged into the IAU editions like other national almanacs.

' is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard et al. in 2003.IAUC 8089: Satellites of Jupiter 2003 March 7 (discovery)MPEC 2003-E29: S/2003 J 9, 2003 J 10, 2003 J 11, 2003 J 12; S/2003 J 1, 2003 J 6 2003 April 3 (discovery and ephemeris) is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 22,731 Mm in 700.129 days, at an inclination of 164° to the ecliptic (166° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.3438.

' is a natural satellite of Jupiter. It was discovered by a team of astronomers led by Brett J. Gladman in 2003.IAUC 8116: Satellites of Jupiter and Saturn 2003 April (discovery)MPEC 2003-G18: S/2003 J 16 2003 April (discovery and ephemeris) is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 20,744 Mm in 610.362 days, at an inclination of 151° to the ecliptic (149° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.3185. It belongs to the Ananke group, retrograde irregular moons which orbit Jupiter between 19.3 and 22.7 Gm, at inclinations of roughly 150°.

Herse , or Jupiter L', previously known by its provisional designation of ', is a natural satellite of Jupiter. It was discovered on 8 February 2003 by the astronomers Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, and Lynne Allen and also by a team of astronomers at the University of Hawaii.Daniel W. E. Green, IAUC 8116: Satellites of Jupiter and Saturn 2003 April 11 (discovery)Brian G. Marsden, MPEC 2003-G19: S/2003 J 17 2003 April 3 (discovery and ephemeris) It was named after Herse 'dew', by some accounts a daughter of Zeus and Selene the moon in Greek mythology,Keightley, p. 55; Hard, p.

The TLM word at the beginning of each subframe of a navigation frame enables the receiver to detect the beginning of a subframe and determine the receiver clock time at which the navigation subframe begins. The HOW word then enables the receiver to determine which specific subframe is being transmitted. There can be a delay of up to 30 seconds before the first estimate of position because of the need to read the ephemeris data before computing the intersections of sphere surfaces. After a subframe has been read and interpreted, the time the next subframe was sent can be calculated through the use of the clock correction data and the HOW.

Tombaugh continued searching for over a decade after the discovery of Pluto, and the lack of further discoveries left him satisfied that no other object of a comparable apparent magnitude existed near the ecliptic. No more trans-Neptunian objects were discovered until 15760 Albion in 1992. However, more recently the relatively bright object has been discovered. It has a relatively high orbital inclination, but at the time of Tombaugh's discovery of Pluto, Makemake was only a few degrees from the ecliptic near the border of Taurus and Aurigabased on Minor Planet Center online Minor Planet Ephemeris Service: March 1, 1930: RA: 05h51m, Dec: +29.0 at an apparent magnitude of 16.

In time standards, dynamical time is the time-like argument of a dynamical theory; and a dynamical time scale in this sense is the realization of a time- like argument based on a dynamical theory: that is, the time and time scale are defined implicitly, inferred from the observed position of an astronomical object via a theory of its motion. A first application of this concept of dynamical time was the definition of the ephemeris time scale (ET). at p.304 In the late 19th century it was suspected, and in the early 20th century it was established, that the rotation of the Earth (i.e.

The data it produced, however, exceeded surveillance requirements, permitting the derivation of missile trajectories, the identification of earth satellite launches, the calculation of a satellite's ephemeris (position and orbit), and the synthesis of booster rocket performance. The success achieved by this fixed-beam radar led to the co-location of a tracking radar (AN/FPS-79), beginning in mid-1964. Together, these radars had the capability for estimating the configuration and dimensions of satellites or missiles and observing the reentry of manned or unmanned vehicles. A second FPS-17 installation was made at Laredo, Texas, which was used primarily as a research and development site.

Brown's objective had been to produce an accurate ephemeris of the Moon, based purely on gravitational theory. For the 'main problem' of the Earth-Moon-Sun system, he calculated terms in longitude and latitude down to an uncertainty of 0.001 arcseconds. He also included perturbations due to the other planets (principally Jupiter and Venus) and also accounted for the more difficult problem of the non-spherical nature of the Earth and Moon. Observations showed that Brown's tables were indeed superior to those of Hansen, which had been in use since 1857, but there was still a large unexplained fluctuation in the Moon's mean longitude of the order of 10 arcseconds.

NASA JPL HORIZONS ephemeris more accurate position, no plot. Observer Location: @sun Commemorative medal depicting the comet, Hamburg, 1681 While the Kirch Comet of 1680–1681 was discovered by—and subsequently named for—Gottfried Kirch, credit must also be given to Eusebio Kino, the Spanish Jesuit priest who charted the comet’s course. During his delayed departure for Mexico, Kino began his observations of the comet in Cádiz in late 1680. Upon his arrival in Mexico City, he published his Exposisión [sic] astronómica de el cometa (Mexico City, 1681) in which he presented his findings. Kino’s Exposisión astronómica is among the earliest scientific treatises published by a European in the New World.

Berberich's proficiency at making calculations was quickly noticed by the astronomy community, with his long- time friend Fritz Cohn noting his "infallible dexterity in arithmetic." In October 1884 he was inducted, as a part-time staff member, into the Astronomical Calculation Institute (ACI), of which Cohn would later become the director. On 1 April 1897, he attained a permanent position at the institute and by December 1903 he was a professor. Initially, Berberich split his time at the institute between assisting in the production of the Berliner Astronomisches Jahrbuch (BAJ) ephemeris and calculating the orbits of comets, with a calculation of his first appearing in Volume 117 of the BAJ.

Six months before Harrington died of throat cancerBAAS 25 (1993) 1496 in 1992, astronomer Myles Standish showed that the supposed discrepancies in the planets' orbits were illusory, the product of overestimating the mass of Neptune. When Neptune's newly determined mass was used in the Jet Propulsion Laboratory Developmental Ephemeris (JPL DE), the supposed discrepancies in the Uranian orbit, and with them the need for a Planet X, vanished. There are no discrepancies in the trajectories of any space probes such as Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2 that can be attributed to the gravitational pull of a large undiscovered object in the outer Solar System.Littmann (1990), p. 204.

By June 1611, Galileo himself had determined that Io's orbital period was 42.5 hours long, only 2.5 minutes longer than the modern estimate. Simon Marius' estimate was only one minute longer in the data published in Mundus Iovalis. The orbital periods generated for Io and the other Jovian satellites provided an additional validation for Kepler's Third Law of planetary motion. From these estimates of the orbital periods of Io and the other Galilean moons, astronomers hoped to generate ephemeris tables predicting the positions of each moon with respect to Jupiter, as well as when each moon would transit the face of Jupiter or be eclipsed by it.

One benefit of such predictions, particularly those of satellite eclipses by Jupiter since they were subject to less observer error, would be determining an observer's longitude on Earth with respect to the prime meridian. By observing an eclipse of a Jovian satellite, an observer could determine the current time at the prime meridian by looking up the eclipse in an ephemeris table. Io was particularly useful for this purpose since its shorter orbital period and closer distance to Jupiter made eclipses more frequent and less affected by Jupiter's axial tilt. Knowing the time at the prime meridian and the local time, the observer's longitude could then be calculated.

Augmentation of a global navigation satellite system (GNSS) is a method of improving the navigation system's attributes, such as accuracy, reliability, and availability, through the integration of external information into the calculation process. There are many such systems in place and they are generally named or described based on how the GNSS sensor receives the external information. Some systems transmit additional information about sources of error (such as clock drift, ephemeris, or ionospheric delay), others provide direct measurements of how much the signal was off in the past, while a third group provides additional vehicle information to be integrated in the calculation process. Service areas of satellite-based augmentation systems (SBAS).

Robert Thomas Cross (1850–1923) became the next Raphael, obtaining the copyright to the publication at some time in the 1870s.Lewis, James R., Astrology Encyclopaedia, Detroit: Gale Research, 1994. Robert Cross Smith was also responsible for popularising the system of astrological house division known as the Placidean, after the Italian monk Placidus de Titus (d. 1668). Placidus house tables, for locations in northern latitudes, are still listed in Raphael's Ephemeris, nowadays issued by W. Foulsham, a British publisher founded in 1819. (They first published Raphael's in 1836.) The latest ephemerides have been calculated using data obtained from the astronomical ephemerides produced by NASA’s Jet Propulsion Laboratory in Pasadena, California.

A total lunar eclipse occurred on 1 March 1504, visible at sunset for the Americas, and later over night over Europe and Africa, and near sunrise over Asia. Christopher Columbus, in an effort to induce the natives of Jamaica to continue provisioning him and his hungry men, successfully intimidated the natives by correctly predicting a total lunar eclipse for 1 March 1504 (visible on the evening of 29 February in the Americas), using the Ephemeris of the German astronomer Regiomontanus.Samuel Eliot Morison, Admiral of the Ocean Sea: A Life of Christopher Columbus, 1942, pp. 653–54. Samuel Eliot Morison, Christopher Columbus, Mariner, 1955, pp. 184-92.

He investigated the effect of using an incorrect ephemeris to determine times of minimum light and analysed the nature of abrupt period changes, concluding that they are non-existent. He indicated that periods of broken contact must be of limited duration due to the formation of a gas stream between the binary components and demonstrated that asymmetric minima are caused by dark magnetic spots. Despite criticism, he predicted the existence of large equal-mass binaries which were discovered in 2007. He developed a technique to observe the light from faint binaries during minimum light when they become invisible at visible wavelengths, using an integrator.

The difference between ET and UT is called ΔT; it changes irregularly, but the long-term trend is parabolic, decreasing from ancient times until the nineteenth century, and increasing since then at a rate corresponding to an increase in the solar day length of 1.7 ms per century (see leap seconds). International Atomic Time (TAI) was set equal to UT2 at 1 January 1958 0:00:00 . At that time, ΔT was already about 32.18 seconds. The difference between Terrestrial Time (TT) (the successor to ephemeris time) and atomic time was later defined as follows: :1977 January 1.000 3725 TT = 1977 January 1.000 0000 TAI, i.e.

Space weather and other effects causes the orbit to change over time so the ephemeris has to be updated periodically. Other signals send out the time as measured by the satellite's onboard atomic clock. By measuring signal times of arrival (TOAs) from at least four satellites, the user's receiver can re- build an accurate clock signal of its own and allows hyperbolic navigation to be carried out. Satellite navigation systems offer better accuracy than any land-based system, are available at almost all locations on the Earth, can be implemented (receiver-side) a modest cost and complexity, with modern electronics, and require only a few dozen satellites to provide worldwide coverage.

The basic operating principle of Transit is similar to the system used by emergency locator transmitters, except that in the latter case the transmitter is on the ground and the receiver is in orbit. Each Transit system satellite broadcast two UHF carrier signals that provided precise time hacks (every two minutes), plus the satellite's six orbital elements and orbit perturbation variables. The orbit ephemeris and clock corrections were uploaded twice each day to each satellite from one of the four Navy tracking and injection stations. This broadcast information allowed a ground receiver to calculate the location of the satellite at any point in time.

With a nearly parabolic trajectory, estimates for the orbital period of this comet have varied from 254,000 to 558,000 years, and even as high as 6.5 million years. (Solution using the Solar System Barycenter. Select Ephemeris Type:Elements and Center:@0) Computing the best-fit orbit for this long-period comet is made more difficult since it underwent a splitting event which may have caused a non-gravitational perturbation of the orbit. The 2008 SAO Catalog of Cometary Orbits shows 195 observations for C/1975 V1 and 135 for C/1975 V1-A, for a combined total of 330 (218 observations were used in the fit).

The Air Force Satellite Control Network (AFSCN), operated by the U.S. Space Force's Space Operation Command, provides support for the operation, control, and maintenance of a variety of United States Department of Defense and some non-DoD satellites. This involves continual execution of Telemetry, Tracking, and Commanding (TT&C;) operations. In addition, the AFSCN provides prelaunch checkout and simulation, launch support, and early orbit support while satellites are in initial or transfer orbits and require maneuvering to their final orbit. The AFSCN provides tracking data to help maintain the catalog of space objects and distributes various data such as satellite ephemeris, almanacs, and other information.

The presence of carbon dioxide on the surface suggests that Titania may have a tenuous seasonal atmosphere of CO2, much like that of the Jovian moon Callisto. Other gases, like nitrogen or methane, are unlikely to be present, because Titania's weak gravity could not prevent them from escaping into space. At the maximum temperature attainable during Titania's summer solstice (89 K), the vapor pressure of carbon dioxide is about 300 μPa (3 nbar). On September 8, 2001, Titania occulted a bright star (HIP 106829) with a visible magnitude of 7.2; this was an opportunity to both refine Titania's diameter and ephemeris, and to detect any extant atmosphere.

He was also a major contributor to the six-volume History of the Serb People (1981–1993), and other important publications such as Serbian Art of the 18th Century (1980), and Serbian Art of the 19th Century (1981). In addition, he authored several important art monographs and studies dealing with cultural heritage of the Serbian Orthodox Church, writing about the monasteries of Hilandar and Savina. Other important works by Medaković include The Chronicles of Serbs in Trieste (1987), Serbs in Vienna, Serbs in Zagreb, Images of Belgrade in Old Etchings, Selected Serbian themes, and Letters. Medaković also penned five books of poetry, and an autobiographical prose cycle titled Ephemeris.

Time standards based on Earth rotation were replaced (or initially supplemented) for astronomical use from 1952 onwards by an ephemeris time standard based on the Earth's orbital period and in practice on the motion of the Moon. The invention in 1955 of the caesium atomic clock has led to the replacement of older and purely astronomical time standards, for most practical purposes, by newer time standards based wholly or partly on atomic time. Various types of second and day are used as the basic time interval for most time scales. Other intervals of time (minutes, hours, and years) are usually defined in terms of these two.

Philip Gretton Dennis, Ed., The Registers of North Luffenham, in the County of Rutland, 1572–1812 Parish Register Society (IV) (London 1896), sub anno. During this time Wing collaborated with William Leybourn (1626–1716), and dated the preface to their jointly-authored work Urania Practica, (published in 1649) from North Luffenham in 1648.Vincent Wing and Will. Leybourn, Urania Practica, or, Practical Astronomy : in VI parts, Containing, I. An explanation of the vulgar notes used every year, with the order how to finde them for ever, in the Julian and Gregorian accompts, both arithmatically, and by new invented tables, II. An ephemeris for 19 years, beginning anno 1648, and ending anno 1667, with astronomical rules and tables ..., III.

A research into the mutual perturbations of Jupiter and Saturn secured for him the prize of the Berlin Academy in 1830, and a memoir on cometary disturbances was crowned by the Paris Academy in 1850. In 1838 he published a revision of the lunar theory, entitled Fundamenta nova investigationis, &c.;, and the improved Tables of the Moon ("Hansen's Lunar Tables")Tables de la lune (Google ebook) based upon it were printed in 1857, at the expense of the British government, their merit being further recognized by a grant of £1000, and by their adoption in the Nautical Almanac as from the issue for the year 1862,Explanatory Supplement to the Astronomical Ephemeris, (London, 1961), sect. 7B, p. 178.

Aoede , also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003. It received the temporary designation '.IAUC 8087: Satellites of Jupiter 2003 March 4 (Discovery)MPEC 2003-E11: S/2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 2003 March 4 (Discovery and ephemeris) Aoede is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 23,044,000 km in 714.657 days, at an inclination of 160° to the ecliptic (162° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.4311.

Hegemone , also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003, and given the temporary designation '.IAUC 8088: S/2003 J 8 2003 March 6 (discovery)MPEC 2003-E24: S/2003 J 8 2003 March 6 (discovery and ephemeris) Hegemone is about 3 kilometres in diameter, and orbits Jupiter at an average distance of 23,703,000 km in 745.500 days, at an inclination of 153° to the ecliptic (151° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.4077. It was named in March 2005 after Hegemone, one of the Graces, and a daughter of Zeus (Jupiter).

Kallichore , also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard, et al. in 2003. It received the temporary designation '.IAUC 8089: Satellites of Jupiter 2003 March 7 (discovery)MPEC 2003-E29: S/2003 J 9, 2003 J 10, 2003 J 11, 2003 J 12; S/2003 J 1, 2003 J 6 2003 April 3 (discovery and ephemeris) Kallichore is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 23,112,000 km in 717.806 days, at an inclination of 165° to the ecliptic (164° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2042.

'Jupiter LV, provisionally known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers led by Brett J. Gladman in 2003.MPEC 2003-G20: S/2003 J 18 April 4, 2003 (discovery) is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 20.220 Gm in 587.38 days, at an inclination of 146° to the ecliptic (148° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.1048.MPEC 2017-L09: S/2003 J 18 June 2, 2017 (recovery and ephemeris) It belongs to the Ananke group, retrograde irregular moons that orbit Jupiter between 22.8 and 24.1 Gm, at inclinations of roughly 150-155°.

Carpo , also ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003, and was provisionally designated as 'MPEC 2003-G67: S/2003 J 20 2003 April (discovery and ephemeris) until it received its name in early 2005. Carpo is about 3 kilometres (1.9 miles) in diameter, and orbits Jupiter at an average distance of 17.145 Gm (just over ten million miles) in 458.625 days, at an inclination of 56° to the ecliptic (55° to Jupiter's equator), and with a high eccentricity of 0.4316. It was named in March 2005 after Carpo, one of the Horae, and a daughter of Zeus (Jupiter).

Eben Jenks Loomis (November 11, 1828 - December 2, 1912) was an American astronomer, born in Oppenheim, New York. He attended the Lawrence Scientific School (Harvard) in 1851-53; was assistant in the American Ephemeris and Nautical Almanac office from 1850 until his retirement in 1900. During this time he also held the position of special assistant at the United States Naval Observatory in Washington, DC.Representative Women of New England by Julia Ward Howe - Google Books, page 277 Loomis was a member of the United States eclipse expedition to Africa in 1889. He is author of Wayside Sketches (1894); An Eclipse Party in Africa (1896); and A Sunset Idyl, and Other Poems (1903).

The first is to assist in the acquisition of satellites at power-up by allowing the receiver to generate a list of visible satellites based on stored position and time, while an ephemeris from each satellite is needed to compute position fixes using that satellite. In older hardware, lack of an almanac in a new receiver would cause long delays before providing a valid position, because the search for each satellite was a slow process. Advances in hardware have made the acquisition process much faster, so not having an almanac is no longer an issue. The second purpose is for relating time derived from the GPS (called GPS time) to the international time standard of UTC.

Having measured the lunar distance and the heights of the two bodies, the navigator can find Greenwich time in three steps. ;Step one – Preliminaries :Almanac tables predict lunar distances between the centre of the Moon and the other body (published between 1767 and 1906 in Britain).The Nautical Almanac and Astronomical Ephemeris, for the year 1767, London: W. Richardson and S. Clark, 1766The Nautical Almanac Abridged for the Use of Seamen, 1924 However, the observer cannot accurately find the centre of the Moon (or Sun, which was the most frequently used second object). Instead, lunar distances are always measured to the sharply lit, outer edge (the limb, not terminator) of the Moon (or of the Sun).

Isaac Israeli ben Joseph or Yitzhak ben Yosef (often known as Isaac Israeli the Younger) was a Spanish-Jewish astronomer/astrologer who flourished at Toledo in the first half of the fourteenth century. He was a pupil of Asher ben Yehiel, at whose request (in 1310) he wrote the astronomical work Yesod Olam, the finest contribution on the subject in Hebrew literature. The book includes chapters on: geometry and trigonometry; the structure and position of the globe; the number and movements of celestial spheres; the time differences in days and nights in various parts of the Earth; the movements of sun and moon; solstices, neomeniæ, eclipses, and leap-years. It also contains astronomical tables (ephemeris) and a perpetual calendar.

When viewed over a one-year period, the mean longitude is very nearly a linear function of Terrestrial Time. To find the length of the tropical year, the mean longitude is differentiated, to give the angular speed of the Sun as a function of Terrestrial Time, and this angular speed is used to compute how long it would take for the Sun to move 360° (; Astronomical Almanac for the year 2011, L8). The above formulae give the length of the tropical year in ephemeris days (equal to 86,400 SI seconds), not solar days. It is the number of solar days in a tropical year that is important for keeping the calendar in synch with the seasons (see below).

Jet Propulsion Laboratory Development Ephemeris (abbreved JPL DE(number), or simply DE(number)) designates one of a series of mathematical models of the Solar System produced at the Jet Propulsion Laboratory in Pasadena, California, for use in spacecraft navigation and astronomy. The models consist of numeric representations of positions, velocities and accelerations of major Solar System bodies, tabulated at equally spaced intervals of time, covering a specified span of years. Barycentric rectangular coordinates of the Sun, eight major planets and Pluto, and geocentric coordinates of the Moon are tabulated. DE405, created in May 1997, include both nutations and librations, and is considered the fundamental planetary and lunar ephemerides of The Astronomical Almanac.

Each ephemeris was produced by numerical integration of the equations of motion, starting from a set of initial conditions. Due to the precision of modern observational data, the analytical method of general perturbations could no longer be applied to a high enough accuracy to adequately reproduce the observations. The method of special perturbations was applied, using numerical integration to solve the n-body problem, in effect putting the entire Solar System into motion in the computer's memory, accounting for all relevant physical laws. The initial conditions were both constants such as planetary masses, from outside sources, and parameters such as initial positions and velocities, adjusted to produce output which was a "best fit" to a large set of observations.

Linda Morabito graduated from the University of Southern California with a B.S. in astronomy in 1974 and did graduate work in computer science at USC. Before receiving her astronomy degree, she joined Jet Propulsion Laboratory for temporary summer employment, and accepted a position after receiving her degree in the Outer Planet Satellite Ephemeris Development Group at Jet Propulsion Laboratory as a senior engineer (1974–1981). In March 1979, she discovered the anomalous "crescent" off the limb of Jupiter’s moon Io in a picture of Io taken by Voyager 1 for navigation, after the Voyager 1 close encounter with Jupiter. She proposed a series of hypotheses and conducted investigations to prove or disprove them, to identify the "crescent".

Meanwhile, the Reeds Nautical Almanac, published by Adlard Coles Nautical, has been in print since 1932, and in 1944 was used by landing craft involved in the Normandy landings. The "Air Almanac" of the United States and Great Britain tabulates celestial coordinates for 10-minute intervals for use in aerial navigation. The Sokkia Corporation's annual "Celestial Observation Handbook and Ephemeris" tabulated daily celestial coordinates (to a tenth of an arcsecond) for the Sun and nine stars; it was last published for 2008. To find the position of a ship or aircraft by celestial navigation, the navigator measures with a sextant the apparent height of a celestial body above the horizon, and notes the time from a marine chronometer.

Einstein's Clocks, Poincare's Maps: empires of time By Peter Louis Galison When the modern SI system was defined at the 10th General Conference on Weights and Measures (CGPM) in 1954, the ephemeris second (1/86400 of a mean solar day) was made one of the system's base units. Because the Earth's rotation is slowly decelerating at an irregular rate and was thus unsuitable as a reference point for precise measurements, the SI second was later redefined more precisely as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. The international standard atomic clocks use caesium-133 measurements as their main benchmark.

In 1858, he left the military and started his own pharmaceutics manufacturing business in Brooklyn. His laboratory burned down three times, and in one of these instances an ether explosion left Squibb badly burned. In 1892, Squibb created a partnership with his two sons, Dr. Edward H. Squibb and Charles F. Squibb, the firm being known for generations afterwards as E. R. Squibb and Sons. Squibb was known as a vigorous advocate of quality control and high purity standards within the fledgling pharmaceutical industry of his time, at one point self-publishing an alternative to the U.S. Pharmacopeia (Squibb's Ephemeris of Materia Medica) after failing to convince the American Medical Association to incorporate higher purity standards.

In 1507, at the instigation of Duke Ulrich I he received the newly established chair of mathematics and astronomy at the University of Tübingen, where he excelled in rich teaching and publication activities and finally was elected rector in 1522. By the time of his appointment he already enjoyed a virtual monopoly in ephemeris-making in collaboration with Jacob Pflaum, continuing the calculations of Regiomontanus through 1531, and then through 1551, the latter being published posthumously in 1531. His treatise on the construction and the use of the astrolabe, entitled Elucidatio fabricae ususque astrolabii, was published in several editions and served astronomers and surveyors for a long time as a standard work.

This confirmed the unsuitability of the mean solar second of Universal Time as a measure of time interval for the most precise purposes. After three years of comparisons with lunar observations, Markowitz et al. (1958) determined that the ephemeris second corresponded to 9 192 631 770 ± 20 cycles of the chosen cesium resonance.W Markowitz, R G Hall, L Essen, J V L Parry (1958) Following this, in 1967/68, the General Conference on Weights and Measures (CGPM) replaced the definition of the SI second by the following: > The second is the duration of 9 192 631 770 periods of the radiation > corresponding to the transition between the two hyperfine levels of the > ground state of the caesium 133 atom.

'Erinome, also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard et al. in 2000, and given the temporary designation .IAUC 7555: Satellites of Jupiter 2001 January 5 (discovery)MPEC 2001-A28: S/2000 J 2, S/2000 J 3, S/2000 J 4, S/2000 J 5, S/2000 J 6 2001 January 5 (discovery and ephemeris) Erinome is about 3.2 kilometres in diameter, and orbits Jupiter at an average distance of 22,986,000 km in 711.965 days, at an inclination of 164° to the ecliptic (162° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2552.

Tarqeq, also known as Saturn LII (provisional designation S/2007 S 1) is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on 13 April 2007 from observations taken between 5 January 2006 and 22 March 2007.MPEC 2007-G38: S/2007 S 1 13 April 2007 (discovery, prediscovery and ephemeris)IAUC 8836: S/2007 S 1, S/2007 S 2, and S/2007 S 3 11 May 2007 (discovery) It is named after Tarqeq, the Inuit moon god,IAUC 8873: Satellites of Saturn 20 September 2007 (naming) and is a member of the Inuit group of irregular satellites. It is about seven kilometres in diameter.

The longitudes of perihelion were only 29 degrees apart at J2000, so the smallest distances, which come when inferior conjunction happens near Earth's perihelion, occur when Venus is near perihelion. An example was the transit of December 6, 1882: Venus reached perihelion Jan 9, 1883, and Earth did the same on December 31. Venus was 0.7205 au from the Sun on the day of transit, decidedly less than average.screenshots from the Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE) ephemeris generator Moving far backwards in time, more than 200,000 years ago Venus sometimes passed by at a distance from Earth of barely less than 38 Gm, and will next do that after more than 400,000 years.

Other possible meanings of a "Julian date" of "36" include an astronomical Julian Day Number, or the year AD 36 in the Julian calendar, or a duration of 36 astronomical Julian years). This is why the terms "ordinal date" or "day-of-year" are preferred. In contexts where a "Julian date" means simply an ordinal date, calendars of a Gregorian year with formatting for ordinal dates are often called "Julian calendars", but this could also mean that the calendars are of years in the Julian calendar system. Historically, Julian dates were recorded relative to Greenwich Mean Time (GMT) (later, Ephemeris Time), but since 1997 the International Astronomical Union has recommended that Julian dates be specified in Terrestrial Time.

632 note At least one mathematical astronomer adopted Herschel's "days of the Julian period" immediately. Benjamin Peirce of Harvard University used over 2,800 Julian days in his Tables of the Moon, begun in 1849 but not published until 1853, to calculate the lunar ephemerides in the new American Ephemeris and Nautical Almanac from 1855 to 1888. The days are specified for "Washington mean noon", with Greenwich defined as west of Washington (282°57′W, or Washington 77°3′W of Greenwich). A table with 197 Julian days ("Date in Mean Solar Days", one per century mostly) was included for the years –4713 to 2000 with no year 0, thus "–" means BC, including decimal fractions for hours, minutes and seconds.

Cyllene , also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003, receiving the temporary designation '.IAUC 8116: Satellites of Jupiter and Saturn 2003 April (discovery)MPEC 2003-G09: S/2003 J 13 2003 April (discovery and ephemeris) Cyllene is about 2 kilometres in diameter, and orbits Jupiter at an average distance of (23.4 million km) 23,396,000 km in 731.099 days (2.00 earth years), at an inclination of 140.149° to the ecliptic (139.543° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.4116. It was named in March 2005 after Cyllene, a naiad (stream nymph) or oread (mountain nymph) associated with Mount Cyllene, Greece.

The first accurate atomic clock, a caesium standard based on a certain transition of the caesium-133 atom, was built by Louis Essen in 1955 at the National Physical Laboratory in the UK. Calibration of the caesium standard atomic clock was carried out by the use of the astronomical time scale ephemeris time (ET). The International System of Units standardized its unit of time, the second, on the properties of cesium in 1967. SI defines the second as 9,192,631,770 cycles of the radiation which corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom. The cesium atomic clock, maintained by the National Institute of Standards and Technology, is accurate to 30 billionths of a second per year.

In 1759, she was again a part of Lalande's team and worked with him to calculate the ephemeris of the transit of Venus. It is not documented what should be attributed to her personally, but in 1761, she was acknowledged by being inducted as an honorary member of the distinguished Scientific Academy of Béziers. Lalande also collaborated with Lepaute for fifteen years on the Academy of Science's annual guides for astronomers and navigators by developing ephemerides: tables that predict the location of the stars on each day of the year, and after her death, wrote a brief biography about her contributions to astronomy. In 1762, Lepaute calculated the exact time of a solar eclipse that occurred on 1 April 1764.

J. Cladel, Maillol. Sa vie, son œuvre, ses idées, Paris, 1937, p.98. In 1948, Carl Blümel published it in a monograph as The Hermes of a Praxiteles,Blümel, Der Hermes eine Praxiteles (Baden-Baden) 1948. reversing his earlier (1927) opinion that it was a Roman copy, finding it not 4th century either but referring it instead to a Hellenistic sculptor, a younger Praxiteles of Pergamon.On the basis of the inscription Pergamon VIII, 1, 137. First suggestion by C. H. Morgan, "The Drapery of the Hermes of Praxiteles", Archaiologike Ephemeris (1937), pp.61–68. Rhys Carpenter dismissed this Praxiteles as a phantom, "Two postscripts to the Hermes controversy", American Journal of Archaeology (January 1954), vol.58, no.1, pp.4–6.

342 A later version of Washington mean time based on the meridian of the clock room at the exact center of the New Naval Observatory (77°4′2.24″W or ) was still being used in 1950 on a few pages of the American Ephemeris and Nautical Almanac, even though most of its pages used Greenwich Civil Time, the American name for the midnight epoch Greenwich Mean Time. For astronomical purposes, before 1925 a day was considered to start at noon rather than the previous midnight. Thus to convert times of astronomical events before 1925 given in Washington mean time to modern Universal Time it is necessary to add an additional 12 hours beyond the meridian difference from Washington to Greenwich, totalling more than 17 hours.

Kale , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered in 2001 by astronomers Scott S. Sheppard, D. Jewitt, and J. Kleyna, and was originally designated as '.IAUC 7900: Satellites of Jupiter 2002 May (discovery)MPEC 2002-J54: Eleven New Satellites of Jupiter 2002 May (discovery and ephemeris) Kale is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 22,409 Mm in 685.324 days, at an inclination of 165° to the ecliptic (166° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2011. It was named in August 2003IAUC 8177: Satellites of Jupiter, Saturn, Uranus 2003 August (naming the moon) after Kale, one of the Charites (Greek Χάριτες, Latin Gratiae, "Graces"), daughters of Zeus (Jupiter).

Skathi , or Saturn XXVII, is a natural satellite of Saturn. It was discovered by Brett Gladman, Kavelaars and colleagues in 2000, and given the temporary designation S/2000 S 8.IAUC 7538: S/2000 S 7, S/2000 S 8, S/2000 S 9 7 December 2000 (discovery) MPEC 2000-Y15: S/2000 S 1, S/2000 S 2, S/2000 S 7, S/2000 S 8, S/2000 S 9 19 December 2000 (discovery and ephemeris) Skathi is about 8 kilometres in diameter and orbits Saturn at an average distance of 15.576 Gm in 725.784 days, at an inclination of 149° to the ecliptic (150° to Saturn's equator), in a retrograde direction and with an eccentricity of 0.246. Its rotation period is hours.

Eurydome , also known as ', is a natural satellite of Jupiter. It was discovered along with Hermippe by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the temporary designation '.IAUC 7900: Satellites of Jupiter 2002 May (discovery)MPEC 2002-J54: Eleven New Satellites of Jupiter 2002 May (discovery and ephemeris) Eurydome is about 3 kilometres in diameter, and orbits Jupiter at an average distance of 23,231,000 km in 723.359 days, at an inclination of 149° to the ecliptic (147° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.3770. It was named in August 2003 after Eurydome in Greek mythology, who is sometimes described as the mother of the Graces by Zeus (Jupiter).

Sponde , also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the temporary designation '.IAUC 7900: Satellites of Jupiter 2002 May 16 (discovery)MPEC 2002-J54: Eleven New Satellites of Jupiter 2002 May 15 (discovery and ephemeris) Sponde is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 24,253,000 km in 771.604 days, at an inclination of 154° to the ecliptic (156° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.443. It was named in August 2003 after one of the Horae (Hours), which presided over the seventh hour (libations poured after lunch).

Kiviuq is a prograde irregular satellite of Saturn. It was discovered by J. J. KavelaarsKavelaars, J. J., et al. The discovery of faint irregular satellites of Uranus Icarus 169 (2004), 474. in 2000, and given the temporary designation S/2000 S 5.IAUC 7521: S/2000 S 5, S/2000 S 6 November 18, 2000 (discovery)MPEC 2000-Y14: S/2000 S 3, S/2000 S 4, S/2000 S 5, S/2000 S 6, S/2000 S 10 December 19, 2000 (discovery and ephemeris) It was named after Kiviuq, a hero of Inuit mythology.IAUC 8177: Satellites of Jupiter, Saturn, Uranus August 8, 2003 (naming the moon) Kiviuq is about in diameter, and orbits Saturn at an average distance of 11.1 million kilometers in 450 days.

Six months before Harrington's death, E. Myles Standish had used data from Voyager 2's 1989 flyby of Neptune, which had revised the planet's total mass downward by 0.5%—an amount comparable to the mass of MarsCroswell (1997), p. 66.—to recalculate its gravitational effect on Uranus. When Neptune's newly determined mass was used in the Jet Propulsion Laboratory Developmental Ephemeris (JPL DE), the supposed discrepancies in the Uranian orbit, and with them the need for a Planet X, vanished. There are no discrepancies in the trajectories of any space probes such as Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2 that can be attributed to the gravitational pull of a large undiscovered object in the outer Solar System.

Consequently, the values of physical constants to be used with calculations using TCB differ from the traditional values of physical constants (The traditional values were in a sense wrong, incorporating corrections for the difference in time scales). Adapting the large body of existing software to change from TDB to TCB is an ongoing task, and many calculations continue to use TDB in some form. Time coordinates on the TCB scale are conventionally specified using traditional means of specifying days, carried over from non-uniform time standards based on the rotation of the Earth. Specifically, both Julian Dates and the Gregorian calendar are used. For continuity with its predecessor Ephemeris Time, TCB was set to match ET at around Julian Date 2443144.5 (1977-01-01T00Z).

ELP gives a series expansion of the orbital elements and the coordinates of the Moon. The authors refer to it as a "semi-analytical" theory because they developed their expressions not purely symbolically, but introduced numerical values for orbital constants from the outset; but they also constructed partial derivatives of all terms with respect to these constants, so they could make corrections afterwards to reach the final solution. ELP has been fitted not directly to observations, but to the numerical integrations known as the Jet Propulsion Laboratory Development Ephemeris (which includes the Lunar Ephemerides), that in their turn have been fitted to actual astronomical observations. ELP was fitted initially to the DE200, but improved parameters have been published up to DE405.

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).

Arche , also known as ', is a moon of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard on 31 October 2002, and received the temporary designation '.IAUC 8035: S/2002 J 1 2002 December 18 (discovery)MPEC 2002-Y22: S/2002 J 1 2002 December 18 (discovery and ephemeris) Arche is about 3 kilometres in diameter, and orbits Jupiter at an average distance of 23,717,000 km in 746.185 days, at an inclination of 165° to the ecliptic (162° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.149. It was named in 2005 after Arche, whom some Greek writers described as one of the four original Muses, an addition to the earlier three (Aoede, Melete, and Mneme).

' is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003.IAUC 8087: Satellites of Jupiter 2003 March 4 (discovery)MPEC 2003-E11: S/2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 2003 March 4 (discovery and ephemeris) is about 2 km in diameter, and orbits Jupiter at an average distance of 23,571,000 km in 739.294 days, at an inclination of 147° to the ecliptic (149° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.3003. It belongs to the Pasiphae group, irregular retrograde moons orbiting Jupiter at distances ranging between 22.8 and 24.1 Gm, and with inclinations ranging between 144.5° and 158.3°.

' is a natural satellite of Jupiter, and is one of the smallest known natural satellites in the Solar System. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003.MPEC 2003-E29: S/2003 J 9, 2003 J 10, 2003 J 11, 2003 J 12; S/2003 J 1, 2003 J 6 April 3, 2003 (discovery and ephemeris) is about 1 kilometre (0.6 miles) in diameter, and orbits Jupiter at an average distance of 17,883 Mm in 489.72 days, at an inclination of 143° to the ecliptic (143° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.4920. It is the innermost of the outer irregular retrograde satellites of Jupiter, and might belong to the Ananke group.

Kore , also known as ', is a natural satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003 and given the provisional designation '.IAUC 8116: Satellites of Jupiter and Saturn 2003 April (discovery)MPEC 2003-G10: S/2003 J 14 2003 April (discovery and ephemeris) Kore is about 2 kilometers in diameter, and orbits Jupiter at an average distance of 23,239,000 km in 723.720 days, at an inclination of 141° to the ecliptic (139° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2462. It belongs to the Pasiphae group, which is made up of irregular retrograde moons orbiting Jupiter at distances ranging between 22.8 and 24.1 Gm, and with inclinations ranging between 144.5° and 158.3°.

In order to completely leave one planet's gravitational field to reach another, a hyperbolic trajectory relative to the departure planet is necessary, with excess velocity added to (or subtracted from) the departure planet's orbital velocity around the Sun. The desired heliocentric transfer orbit to a superior planet will have its perihelion at the departure planet, requiring the hyperbolic excess velocity to be applied in the posigrade direction, when the spacecraft is away from the Sun. To an inferior planet destination, aphelion will be at the departure planet, and the excess velocity is applied in the retrograde direction when the spacecraft is toward the Sun. For accurate mission calculations, the orbital elements of the planets must be obtained from an ephemeris, such as that published by NASA's Jet Propulsion Laboratory.

A fundamental ephemeris is the basis from which apparent ephemerides, phenomena, and orbital elements are computed for astronomical, nautical, and surveyors' almanacs. Apparent ephemerides give positions and motions of Solar System bodies as seen by observers from the surface of Earth, and are useful for astronomers, navigators, and surveyors in planning observations and in reducing the data acquired, although much of the work of latter two has been supplanted by GPS technology. Phenomena are events related to the configurations of Solar System bodies, for instance rise and set times, phases, eclipses and occultations, and have many civil and scientific applications. Orbital elements are descriptions of the motion of a body at a particular instant, used for further short-time-span calculation of the body's position when high accuracy is not required.

Brown's Tables were adopted by nearly all of the national ephemerides in 1923 for their calculations of the Moon's position, and continued to be used with some modification until 1983. With the advent of digital computers, Brown's original trigonometrical expressions, given in the introduction to his 1919 tables (and from which the tables had been compiled), began to be used for direct computation instead of the tables themselves. This also gained some improvement in precision, since the tables had embodied some minor approximations, in a trade-off between accuracy and the amount of labour needed for computations in those days of manual calculation. By the middle of the 20th century, the difference between Universal and Ephemeris Time had been recognised and evaluated, and the troublesome empirical terms were removed.

The squadron initially made orbital predictions by computing ephemerides based on standard Kepler orbits. As a satellite got lower into the atmosphere, drag made it difficult to forecast the ephemeris of the satellite accurately.Cotter, Lawrence R.. Reminiscences About Space Track History. Privately published. Berkeley CA, 20 November 2006. By 1962, the situation was somewhat better. The Soviet satellite Sputnik 4 was slowly entering lower orbits because of atmospheric drag. Using a new program, (Satellite General Perturbations Differential Corrections) and observations from the radar at Shemya Air Force Station, the orbital analyst plotted the changing orbital period and was able to predict the exact revolution on which the satellite reentered the atmosphere.A 20-pound piece of it landed on a street in downtown Manitowoc, Wisconsin on the western shore of Lake Michigan.

589 On the 23rd, Thome recorded a tail length of over 40 degrees, but like other observers stated he could not find a nucleus. On January 27, C. Todd recorded seeing the comet's head as a "diffused nebulous mass", but noted a break between the head and the tail (possibly representing what is referred to as a tail disconnection event). Following the publication of an ephemeris by S. C. Chandler, which suggested the comet could be located 20° from Rigel by the end of February, astronomers in the United States eagerly waited for it to move far enough into northern skies to be visible."Lost Tramp of the Skies - The Great Southern Comet Disappears", New York Times, February 27, 1887 However, the comet faded extremely rapidly, and never became visible from northern latitudes.

In the former case, values based on right ascension and declination are obtained. Right ascension is longitude, measured eastwards, on the celestial equator – the earth’s equator projected into space to encircle the solar system. Declination is the other co-ordinate, measured north to south, on this hypothetical, great sphere. The astrological ephemeris was developed for the purposes of setting up a birth chart, or horoscope, and converts positions of planets given in right ascension/declination into zodiacal longitude. This is a planet’s position along the ecliptic –the plane of the earth’s orbit around the sun, or the sun’s apparent path around a fixed, stationary earth. An astrological birth chart is geocentric, or earth-centred, calculated as if the earth was at a fixed point, with the zodiac ‘revolving’ around it.

Raphael’s Ephemeris was first issued as part of an almanac entitled The Prophetic Messenger in the early nineteenth century. ‘Raphael’, the name given to one of three archangels in the Old Testament, was used as a pseudonym byRobert Cross Smith (1795–1832), a former carpenter who had developed an interest in astrology. Smith first used the pseudonym in 1824 when he edited a periodical called The Straggling Astrologer, later re-published as The Astrologer of the Nineteenth Century. He also referred to himself as the ‘Royal Merlin’.Howe, Ellic, The Royal Merlin, London: Arborfield, 1964. The Straggling Astrologer was a relative failure, but by 1827 Smith had assumed editorship of The Prophetic Messenger, which was read widely by astrologers of the day, and contributed to a renaissance of interest in astrology in the nineteenth century.

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.

Harrington died in January 1993, without having found Planet X.Croswell (1997), p. 66. Six months before, E. Myles Standish had used data from Voyager 2's 1989 flyby of Neptune, which had revised the planet's total mass downward by 0.5%—an amount comparable to the mass of Mars—to recalculate its gravitational effect on Uranus. When Neptune's newly determined mass was used in the Jet Propulsion Laboratory Developmental Ephemeris (JPL DE), the supposed discrepancies in the Uranian orbit, and with them the need for a Planet X, vanished. There are no discrepancies in the trajectories of any space probes such as Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2 that can be attributed to the gravitational pull of a large undiscovered object in the outer Solar System.

In the Ratchet & Clank comic series and All 4 One, Qwark confirms that Lawrence teleported Nefarious away in time and that he is still considered to be within the Polaris System. Doctor Nefarious is a playable character in the game Ratchet & Clank: All 4 One, where he initially triggers the plot by tricking Qwark into fighting a giant Light-eating Z'Grute only to be attacked by his own creature. When Ratchet and Clank try to stop it, they, Qwark, and Nefarious are all captured by the Creature Collector Ephemeris, and the villainous robot is forced to work with the heroes to escape. Despite his dislike of his "partners", Nefarious slowly warms up to playing the hero, even going so far as to save Qwark on a few occasions.

For instance, as the density required to spin at such high rates are comparable to nuclear densities, the fastest spinning millisecond pulsars are important in understanding how matter behaves at such densities. The initially high estimate of the spin down rate was also intriguing, as it implied a signal that could be directly detected by gravitational wave detectors, but the actual spin down rate put the expected signal below the sensitivity of current detectors. The currently accepted value spin down rate corresponds to a change in the rotational period of 1.5 Hz over the course of one million years. The stability of rotation of PSR B1937+21 is of the same order of the stability of the best atomic clocks, and is thus a tool used in establishing ephemeris time.

Harpalyke , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000, and given the temporary designation '.IAUC 7555: Satellites of Jupiter January 5, 2001 (discovery)MPEC 2001-A28: S/2000 J 2, S/2000 J 3, S/2000 J 4, S/2000 J 5, S/2000 J 6 January 5, 2001 (discovery and ephemeris) In August 2003, the moon was namedIAUC 7998: Satellites of Jupiter 2002 October 22 (naming the moon) after Harpalyke, the incestuous daughter of Clymenus, who in some accounts was also a lover of Zeus (Jupiter). Harpalyke belongs to the Ananke group, believed to be the remnants of a break-up of a captured heliocentric asteroid.

Hermippe , or ', is a natural satellite of Jupiter. It was discovered along with Eurydome by a team of astronomers from the Institute for Astronomy of the University of Hawaii led by David Jewitt and Scott S. Sheppard and Jan Kleyna in 2001, and given the temporary designation '.IAUC 7900: Satellites of Jupiter May 16, 2002 (discovery)MPEC 2002-J54: Eleven New Satellites of Jupiter May 15, 2002 (discovery and ephemeris) Hermippe is about 4 kilometres in diameter, and orbits Jupiter at an average distance of 21,500,000 kilometers in about 630 days, at an inclination of 151° to the ecliptic (149° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2290. It was named in August 2003 by the IAU, after Hermippe, a lover of Zeus (Jupiter).

Pasithee , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2001, and given the temporary designation '.IAUC 7900: Satellites of Jupiter May 16, 2002 (discovery)MPEC 2002-J54: Eleven New Satellites of Jupiter May 15, 2002 (discovery and ephemeris) Pasithee is about 2 kilometres in diameter, and orbits Jupiter at an average distance of 23,307,000 km in 727.933 days, at an inclination of 166° to the ecliptic (164° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.3289. It was named in August 2003 after Pasithee, one of the Charites, goddesses of charm, beauty, nature, human creativity and fertility, daughters of Zeus (Jupiter) by Eurynome.

Kalyke , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard et al. in 2000, and given the temporary designation '.IAUC 7555: Satellites of Jupiter 2001 January 5 (discovery)MPEC 2001-A28: S/2000 J 2, S/2000 J 3, S/2000 J 4, S/2000 J 5, S/2000 J 6 2001 January 5 (discovery and ephemeris) From infrared thermal measurements by the WISE spacecraft, Kalyke's albedo is measured at 2.9%, corresponding to a diameter of 6.9 kilometres. It orbits Jupiter at an average distance of 23,181,000 km in 721.021 days, at an inclination of 166° to the ecliptic (165° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.2140.

After the difficulties were appreciated, in 1991 the IAU refined the official definitions of timescales by creating additional new time scales: Barycentric Coordinate Time (TCB) and Geocentric Coordinate Time (TCG). TCB was intended as a replacement for TDB, and TCG was its equivalent for use in near-Earth space. TDT was also renamed to Terrestrial Time (TT), because of doubts raised about the appropriateness of the word "dynamical" in that connection. In 2006 TDB was redefined by IAU 2006 resolution 3; the 'new' TDB was expressly acknowledged as equivalent for practical purposes to JPL ephemeris time argument Teph; the difference between TDB according to the 2006 standard and TT (both as observed from the surface of the Earth), remains under 2 ms for several millennia around the present epoch.

As is well known, the 9192631770 figure was chosen for the SI second. L Essen in the same 1968 article (p.162) stated that this "seemed reasonable in view of the variations in UT2".) The small difference accumulates over time, which leads to an increasing difference between our clock time (Universal Time) on the one hand, and Atomic Time and Ephemeris Time on the other hand: see ΔT. This led to the introduction of the leap second in 1972 to compensate for differences in the bases for time standardization. In addition to the effect of the ocean tides, there is also a tidal acceleration due to flexing of Earth's crust, but this accounts for only about 4% of the total effect when expressed in terms of heat dissipation.

A-GPS has two modes of operation: ;Mobile Station Assisted (MSA): In MSA mode A-GPS operation, the A-GPS capable device receives acquisition assistance, reference time and other optional assistance data from a mobile service provider. The mobile service provider continuously logs GPS information (mainly the almanac) from the GPS satellites using an A-GPS server in its system. With the help of the above data (the data received from the mobile device and the data already present in an A-GPS server) the A-GPS server calculates the position and sends it back to the A-GPS device. ;Mobile Station Based (MSB): In MSB mode A-GPS operation, the A-GPS device receives ephemeris, reference location, reference time and other optional assistance data from the A-GPS server.

' is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2003.IAUC 8089: Satellites of Jupiter 7 March 2003 (discovery)MPEC 2003-E29: S/2003 J 9, 2003 J 10, 2003 J 11, 2003 J 12; S/2003 J 1, 2003 J 6 3 April 2003 (discovery and ephemeris) is about 1 kilometre in diameter, and orbits Jupiter at an average distance of 23,858 Mm in 752.839 days, at an inclination of 165° to the ecliptic (165° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.276. It belongs to the Carme group, made up of irregular retrograde moons orbiting Jupiter at a distance ranging between 23 and 24 Gm and at an inclination of about 165°.

Supplemented by further use of VSOP87. The last three aphelia were 30.33 AU, the next is 30.34 AU. The perihelia are even more stable at 29.81 AU On 11 July 2011, Neptune completed its first full barycentric orbit since its discovery in 1846, although it did not appear at its exact discovery position in the sky, because Earth was in a different location in its 365.26-day orbit. Because of the motion of the Sun in relation to the barycentre of the Solar System, on 11 July Neptune was also not at its exact discovery position in relation to the Sun; if the more common heliocentric coordinate system is used, the discovery longitude was reached on 12 July 2011. (Bill Folkner at JPL)—Numbers generated using the Solar System Dynamics Group, Horizons On-Line Ephemeris System.

The 22nd Space Operations Squadron (22nd SOPS) operates the Air Force Satellite Control Network (AFSCN) by developing, executing and enforcing the Space Access Tasking Order (SpATO) and providing space safety analysis to conduct satellite operations. The 22nd SOPS coordinates the launch and on-orbit operations of more than 190 Department of Defense, national intelligence, civil and Allied nation's satellites, including in support of global warfighters, intelligence community users, the President and Secretary of Defense. The 22nd SOPS's Operations Center at Schreiver AFB, Colorado, develops, publishes and enforces the SpATO, and directs and monitors all aspects of enterprise operations for AFSCN users through a combination of military commanders, civilian professionals and contract support. The squadron's orbit analysts coordinate ephemeris data, launch and early orbit analysis determination, and tracking station look angles to support space operations for some 29 different space operations centers.

Isonoe , also known as ', is a retrograde irregular satellite of Jupiter. It was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000, and given the temporary designation '.IAUC 7555: Satellites of Jupiter 2001 January 5 (discovery)MPEC 2001-A28: S/2000 J 2, S/2000 J 3, S/2000 J 4, S/2000 J 5, S/2000 J 6 2001 January 5 (discovery and ephemeris) Isonoe is about 3.8 kilometres in diameter, and orbits Jupiter at an average distance of 23,833,000 Km in 751.647 days, at an inclination of 166° to the ecliptic (169° to Jupiter's equator), in a retrograde direction and with an eccentricity of 0.166. It was named in October 2002 after Isonoe, one of the Danaïdes in Greek mythology, and a lover of Zeus (Jupiter).

Coley acted as William Lilly's amanuensis from 1677, when the latter was stricken with the illness of which he eventually died. The editor of Lilly's Autobiography tells us: "His judgments and observations for the succeeding years till his death were all composed by his directions, Mr. Coley coming to Hersham the beginning of every summer, and stayed there till by conference with him he had despatched them for the press; to whom at these opportunities he communicated his way of judgment and other 'Arcana. Lilly constantly makes reference in his works to Coley's merit as a man and as a professor of mathematics and occult science. On his death in 1681, Lilly bequeathed to him his almanac Merlini Anglici Ephemeris, or Astrological Judgment for the Year, which had reached its thirty-sixth year of publication; from 1681 it was issued by Coley "according to the method of Mr. Lilly.

Erriapus , or Saturn XXVIII (28), is a prograde irregular satellite of Saturn. It was discovered by Brett Gladman, John J. Kavelaars and colleagues in 2000, and given the temporary designation S/2000 S 10.IAUC 7539: S/2000 S 10 December 7, 2000 (discovery)MPEC 2000-Y14: S/2000 S 3, S/2000 S 4, S/2000 S 5, S/2000 S 6, S/2000 S 10 December 19, 2000 (discovery and ephemeris) It was named Erriapo in August 2003IAUC 8177: Satellites of Jupiter, Saturn, Uranus August 8, 2003 (naming the moon) after Erriapus (also rendered Erriappus), a giant in Gaulish mythology; the name was changed from dative Erriapo to nominative Erriapus per IAU conventions in late 2007.IAUC 9191: SATURN XXVIII (ERRIAPUS) January 11, 2011 Erriapus is about 10 kilometres in diameter, and orbits Saturn at an average distance of 17,3 Gm in 871 days.

As UT is thus slightly irregular in its rate, astronomers introduced Ephemeris Time, which has since been replaced by Terrestrial Time (TT). Because Universal Time is determined by the Earth's rotation, which drifts away from more precise atomic-frequency standards, an adjustment (called a leap second) to this atomic time is needed since () 'broadcast time' remains broadly synchronised with solar time. Thus, the civil broadcast standard for time and frequency usually follows International Atomic Time closely, but occasionally step (or "leap") in order to prevent them from drifting too far from mean solar time. Barycentric Dynamical Time (TDB), a form of atomic time, is now used in the construction of the ephemerides of the planets and other solar system objects, for two main reasons.. Strictly speaking, a major producer of ephemerides, the Jet Propulsion Laboratory, uses a time scale they derive, Teph, which is functionally equivalent to TDB.

' is a retrograde irregular satellite of Jupiter. The discovery, by a team of astronomers from the University of Hawaii led by Scott S. Sheppard and David C. Jewitt, was announced on March 4, 2003.IAUC 8087: Satellites of Jupiter 2003 March 4 (discovery) It is Jupiter's outermost known moon . is about in diameter, and orbits Jupiter at an average distance of about 29,500,000 kilometers () in 981.55 days, at an inclination of 154° to the ecliptic (152° to Jupiter's equator) and with an eccentricity of 0.4100.MPEC 2003-E11: S/2003 J 1, 2003 J 2, 2003 J 3, 2003 J 4, 2003 J 5, 2003 J 6, 2003 J 7 2003 March 4 (discovery and ephemeris)Mean orbital elements from NASA JPL (August 2006)Current (2004 July 14, JD= 2453200.5) orbital elements as reported by IAU-MPC NSES are a= 0.2024818 AU, e=0.1882469 i=153.52114 It may belong to the Pasiphae group, though its orbit is not known well enough to confirm the assignment.

In 1956, a slightly more precise value of was adopted for the definition of the second by the International Committee for Weights and Measures, and in 1960 by the General Conference on Weights and Measures, becoming a part of the International System of Units (SI). Eventually, this definition too was found to be inadequate for precise time measurements, so in 1967, the SI second was again redefined as 9,192,631,770 periods of the radiation emitted by a caesium-133 atom in the transition between the two hyperfine levels of its ground state. That value agreed to 1 part in 1010 with the astronomical (ephemeris) second then in use.Wm Markowitz (1988) 'Comparisons of ET (Solar), ET (Lunar), UT and TDT', in (eds.) A K Babcock & G A Wilkins, 'The Earth's Rotation and Reference Frames for Geodesy and Geophysics', IAU Symposia #128 (1988), at pp 413–418. It was also close to of the mean solar day as averaged between years 1750 and 1892.

The year is not selectable, so it is necessary to know the year currently set, or by looking up the cycles indicated by the various calendar cycle indicators on the back in the Babylonian ephemeris tables for the day of the year currently set, since most of the calendar cycles are not synchronous with the year. The crank moves the date pointer about 78 days per full rotation, so hitting a particular day on the dial would be easily possible if the mechanism were in good working condition. The action of turning the hand crank would also cause all interlocked gears within the mechanism to rotate, resulting in the simultaneous calculation of the position of the Sun and Moon, the moon phase, eclipse, and calendar cycles, and perhaps the locations of planets. The operator also had to be aware of the position of the spiral dial pointers on the two large dials on the back.

High-precision ephemerides of sun, moon and planets were developed and calculated at the Jet Propulsion Laboratory (JPL) over a long period, and the latest available were adopted for the ephemerides in the Astronomical Almanac starting in 1984. Although not an IAU standard, the ephemeris time argument Teph has been in use at that institution since the 1960s. The time scale represented by Teph has been characterized as a relativistic coordinate time that differs from Terrestrial Time only by small periodic terms with an amplitude not exceeding 2 milliseconds of time: it is linearly related to, but distinct (by an offset and constant rate which is of the order of 0.5 s/a) from the TCB time scale adopted in 1991 as a standard by the IAU. Thus for clocks on or near the geoid, Teph (within 2 milliseconds), but not so closely TCB, can be used as approximations to Terrestrial Time, and via the standard ephemerides Teph is in widespread use.

Meridian four blocks north of Old Naval Observatory, looking south in August 2005.Coordinates of "The American Meridian" line in sidewalk of H Street NW at 24th Street NW, in southeast corner of intersection: The third meridian was defined on September 28, 1850 by Congress: "[T]he meridian of the observatory at Washington shall be adopted and used as the American meridian for all astronomical purposes and ... the meridian of Greenwich shall be adopted for all nautical purposes."9 Statutes at Large 515 The observatory decided that this meridian passed through the center of the original (small) dome atop the main building of the Old Naval Observatory, now abandoned southwest of the corner of E and 23rd Streets in Foggy Bottom (north of the Lincoln Memorial and west of the White House). The observatory adopted for its meridian in the American Ephemeris and Nautical Almanac for the years 1855 to 1869 (as .

Consequently, the values of physical constants to be used with calculations using TCG differ from the traditional values of physical constants. (The traditional values were in a sense wrong, incorporating corrections for the difference in time scales.) Adapting the large body of existing software to change from TDB (Barycentric Dynamical Time) to TCG is a formidable task, and as of 2002 many calculations continue to use TDB in some form. Time coordinates on the TCG scale are conventionally specified using traditional means of specifying days, carried over from non- uniform time standards based on the rotation of the Earth. Specifically, both Julian Dates and the Gregorian calendar are used. For continuity with its predecessor Ephemeris Time, TCG was set to match ET at around Julian Date 2443144.5 (1977-01-01T00Z). More precisely, it was defined that TCG instant 1977-01-01T00:00:32.184 exactly corresponds to TAI instant 1977-01-01T00:00:00.000 exactly.

Newcomb's Tables of the Sun (full title Tables of the Motion of the Earth on its Axis and Around the Sun) is a work by the American astronomer and mathematician Simon Newcomb, published in volume VI of the serial publication Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac.Simon Newcomb, Tables of the Four Inner Planets, 1-169. The work contains Newcomb's mathematical development of the position of the Earth in the Solar System, which is constructed from classical celestial mechanics as well as centuries of astronomical measurements. The bulk of the work, however, is a collection of tabulated precomputed values that provide the position of the sun at any point in time. Newcomb's Tables were the basis for practically all ephemerides of the Sun published from 1900 through 1983, including the annual almanacs of the U.S. Naval Observatory and the Royal Greenwich Observatory. The physical tables themselves were used by the ephemerides from 1900 to 1959, computerized versions were used from 1960 to 1980, and evaluations of the Newcomb's theories were used from 1981 to 1983.

In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving the positions and velocities of astronomical objects in the sky at a given time or times.

From 1920 to 1923, he taught Italian and German at Bucharest's Matei Basarab High School. Moving to Italy in 1923, he was a member of the Accademia di Romania for the next two years. In 1929, he became associate professor of Romanian language and literature at Sapienza University of Rome, rising to full professor in 1936. His work appeared in the publications of the Accademia, Ephemeris Dacoromana and Diplomatarium italicum; in Codrul Cosminului, Il giornale di politica e di letteratura, Roma, L’Europa Orientale, Termini, Revista germaniștilor români, Meridiano di Roma, Rassegna Italo-Romena, Revue de Culture, Européenne, Atti dell’Academia degli Arcadi, Le vie d’Oriente, Cahiers „Sextil Pușcariu”, Il libro italiano del mondo, L’illustrazione toscana; in the bound volumes put out by the Romanian Academy, and in various Italian academic publications. A researcher in the traditional mode of cultural and literary relations between Romania and Italy, he published the studies L’Italia e le origini della nuova letteratura romena (1929), La stampa periodica romeno-italiana in Romania e in Italia (1937) and Saggi romeno-italo-ispanici (1943), as well as exegeses on the works of Ion Codru-Drăgușanu and Gheorghe Asachi.

Anthony Aveni asserts, "Once a Maya genius may have recognized that somewhere deep within the calendar system lay the miraculous union, the magical crossing point of a host of time cycles: 9 moons, 13 times 20, a birth cycle, a planting cycle, a Venus cycle, a sun cycle, an eclipse cycle. The number 260 was tailor made for the Maya".Aveni (2000, p.202). Others have observed that the "Venus Table" in the Dresden Codex, is an accurate ephemeris for predicting Venus positions. Others have also observed a basis for the 260-day cycle in the agricultural cycle of highland Guatemala, which is also about 260 days. Aveni notes that "the average duration between successive halves of the eclipse season, at 173 ½ days, fits into the tzolkin in the ratio of 3 to 2."Aveni (2000, p.201). This may seem contrived, but the Maya did employ the tzolkin to predict positions of Venus and eclipses. Another theory is that the 260-day period is the length of human pregnancy. This is close to the average number of days between the first missed menstrual period and birth, unlike Naegele's rule which is 40 weeks (280 days) between the last menstrual period and birth.