Composition-wise, the song "draws on nursery rhyme sensibilities: nihilism, the slow gruesome peaks and troughs of civilisation thinly veiled by dead-eyed cuteness/deranged pop melodies, misanthropy. It reads like the spiritual disfigurement of 'A Ring around the Rosie', appropriated and cosmically aberrated to echo in the year 2018." Kitschin's distorted bass playing on this song has been described as "all-consuming".
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Figure 2. Young's experiment – single- versus double-slit patterns Another common-path interferometer useful in lens testing and fluid flow diagnostics is the point diffraction interferometer (PDI), invented by Linnik in 1933. The reference beam is generated by diffraction from a small pinhole, about half the diameter of the Airy disk, in a semitransparent plate. Fig. 1 illustrates an aberrated wavefront focused onto the pinhole.
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An imperfect, aberrated imaging system could possess the optical transfer function depicted in the following figure. As the ideal lens system, the contrast reaches zero at the spatial frequency of 500 cycles per millimeter. However, at lower spatial frequencies the contrast is considerably lower than that of the perfect system in the previous example. In fact, the contrast becomes zero on several occasions even for spatial frequencies lower than 500 cycles per millimeter.
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It is normally used without any coating on either surface, so as to minimize ghost reflections. An aberrated wavefront from a lens under test is reflected from the front and back of the plate to form the interference pattern. Variations on this basic design allow testing of mirrors. Other forms of lateral shearing interferometer, based on the Jamin, Michelson, Mach–Zehnder, and other interferometer designs, have compensated paths and may be used with white light.
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Coma, or comatic aberration, derives its name from the comet-like appearance of the aberrated image. Coma occurs when an object off the optical axis of the lens is imaged, where rays pass through the lens at an angle to the axis θ. Rays that pass through the centre of a lens of focal length f are focused at a point with distance from the axis. Rays passing through the outer margins of the lens are focused at different points, either further from the axis (positive coma) or closer to the axis (negative coma).
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Unfortunately, there is no standard bucket size (D86 width, Gaussian beam width, Airy disk nulls, etc.) or bucket shape (circular, rectangular, etc.) and there is no standard beam to compare for the Strehl ratio. Therefore, these definitions must always be specified before a number is given and it presents much difficulty when trying to compare lasers. There is also no simple conversion between M2, power-in-the-bucket, and Strehl ratio. The Strehl ratio, for example, has been defined as the ratio of the peak focal intensities in the aberrated and ideal point spread functions.
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The diffraction theory of point spread functions was first studied by Airy in the nineteenth century. He developed an expression for the point spread function amplitude and intensity of a perfect instrument, free of aberrations (the so-called Airy disc). The theory of aberrated point spread functions close to the optimum focal plane was studied by Zernike and Nijboer in the 1930–40s. A central role in their analysis is played by Zernike's circle polynomials that allow an efficient representation of the aberrations of any optical system with rotational symmetry.
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One night, Freddie finds himself in San Francisco and stows away on the yacht of a follower of Lancaster Dodd, the leader of a nascent philosophical movement known as "The Cause". When he is discovered, Dodd describes Freddie as "aberrated" and claims he has met him in the past but cannot remember where. He invites Freddie to stay and attend the marriage of his daughter, Elizabeth, as long as he will make more moonshine, which Dodd has developed a taste for. Dodd begins an exercise with Freddie called "Processing", in which he asks Freddie a flurry of disturbing psychological questions.
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A perfect lens system will provide a high contrast projection without shifting the periodic pattern, hence the optical transfer function is identical to the modulation transfer function. Typically the contrast will reduce gradually towards zero at a point defined by the resolution of the optics. For example, a perfect, non-aberrated, f/4 optical imaging system used, at the visible wavelength of 500 nm, would have the optical transfer function depicted in the right hand figure. It can be read from the plot that the contrast gradually reduces and reaches zero at the spatial frequency of 500 cycles per millimeter, in other words the optical resolution of the image projection is 1/500 of a millimeter, or 2 micrometer.
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The main criticisms of the original design are (1) that the required low-transmission reduces the efficiency, and (2) when the beam becomes too aberrated, the intensity on-axis is reduced, and less light is available for the reference beam, leading to a loss of fringe contrast. Lowered transmission was associated with lowered signal to noise ratio. These problems are largely overcome in the phase-shifting point diffraction interferometer designs, in which a grating or beamsplitter creates multiple, identical copies of the beam that is incident on an opaque mask. The test beam passes through a somewhat large hole or aperture in the membrane, without losses due to absorption; the reference beam is focused onto the pinhole for highest transmission.
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An artist's impression of adaptive optics. The wavefront of an aberrated image (left) can be measured using a wavefront sensor (center) and then corrected for using a deformable mirror (right) Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effect of incoming wavefront distortions by deforming a mirror in order to compensate for the distortion. It is used in astronomical telescopes and laser communication systems to remove the effects of atmospheric distortion, in microscopy, optical fabrication and in retinal imaging systems to reduce optical aberrations. Adaptive optics works by measuring the distortions in a wavefront and compensating for them with a device that corrects those errors such as a deformable mirror or a liquid crystal array.
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Analysis of the flawed images revealed that the primary mirror had been polished to the wrong shape. Although it was believed to be one of the most precisely figured optical mirrors ever made, smooth to about 10 nanometers, the outer perimeter was too flat by about 2200 nanometers (about mm or inch). This difference was catastrophic, introducing severe spherical aberration, a flaw in which light reflecting off the edge of a mirror focuses on a different point from the light reflecting off its center. The effect of the mirror flaw on scientific observations depended on the particular observation—the core of the aberrated PSF was sharp enough to permit high- resolution observations of bright objects, and spectroscopy of point sources was affected only through a sensitivity loss.
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Wide Field and Planetary Camera view of Jupiter, 1991 WFPC image of Messier 100 (NGC 4321) The Wide Field/Planetary Camera (WFPC) (pronounced as wiffpick (Operators of the WFPC1 were known as "whiff-pickers")) was a camera installed on the Hubble Space Telescope launched in April 1990 and operated until December 1993. It was one of the instruments on Hubble at launch, but its functionality was severely impaired by the defects of the main mirror optics which afflicted the telescope. However, it produced uniquely valuable high resolution images of relatively bright astronomical objects, allowing for a number of discoveries to be made by HST even in its aberrated condition. WFPC was proposed by James A. Westphal, a professor of planetary science at Caltech, and was designed, constructed, and managed by JPL.
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Once it had been identified in 1990 that primary mirror in the recently launched Hubble Space Telescope (HST) was defective due to it having been ground to the wrong shape engineers at NASA came under immense pressure to fix the problem. The incorrect shape of the mirror introduced severe spherical aberration, a flaw in which light reflecting off the edge of a mirror focuses on a different point from the light reflecting off its center. The effect of the flaw on scientific observations depended on the particular observation—the core of the aberrated point spread function was sharp enough to permit high-resolution observations of bright objects, and spectroscopy of point sources was affected only through a sensitivity loss. However, the loss of light to the large, out- of-focus halo severely reduced the usefulness of the telescope for faint objects or high-contrast imaging.
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" He characterized "promiscuity, perversion, sadism, and irregular practices" as well as "free love, easy marriage and quick divorce" as being undesirable activities, "since it is non- survival not to have a well ordered system for the creation and upbringing of children, by families." Such "sexual perverts" engaged in "irregular practices which do anything but tend toward the creation of children" and "efforts [which] tend not towards enjoyment but toward the pollution and derangement of sex itself so as to make it as repulsive as possible to others and so to inhibit procreation." Hubbard's 1951 book Handbook for Preclears likewise classified homosexuality as "about 1.1 (covert hostility) on the tone scale", along with "general promiscuity". He set out what he saw as the cause of homosexuality: a mental "aberration", with the result that "an individual aberrated enough about sex will do strange things to be a cause or an effect.
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