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Meniscus Corrector
A meniscus corrector is a negative meniscus lens that is used to correct spherical aberration in image-forming optical systems such as catadioptric telescopes. It works by having the equal but opposite spherical aberration of the objective it is designed to correct (usually a spherical mirror).Contents1 Types 2 Invention 3 See also 4 References 5 Further readingTypes[edit] Meniscus correctors are used as full aperture correctors, most commonly in a Maksutov telescope
Maksutov telescope
sub type called the Gregory or “spot” Maksutov–Cassegrain telescope. They are also used in the Bouwers meniscus telescope. There are Maksutov variations that use the same principle but place the meniscus lens as a sub-aperture corrector near the focus of the objective
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Spherical Aberration
Tilt Spherical aberration Astigmatism Coma Distortion Petzval field curvature Chromatic aberration Spherical aberration
Spherical aberration
is an optical effect observed in an optical device (lens, mirror, etc.) that occurs due to the increased refraction of light rays when they strike a lens or a reflection of light rays when they strike a mirror near its edge, in comparison with those that strike nearer the centre. It signifies a deviation of the device from the norm, i.e., it results in an imperfection of the produced image.On top is a depiction of a perfect lens without spherical aberration: all incoming rays are focused in the focal point.The bottom example depicts a real lens with spherical surfaces, which produces spherical aberration: The different rays do not meet after the lens in one focal point
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Mangin Mirror
In optics, a Mangin mirror is a negative meniscus lens with the reflective surface on the rear side of the glass forming a curved mirror that reflects light without spherical aberration. This reflector was invented in 1876 by a French officer Alphonse Mangin [1][2] as an improved catadioptric reflector for search lights and is also used in other optical devices.Contents1 Description 2 Applications 3 Notes 4 External linksDescription[edit] The Mangin mirror's construction consists of a concave (negative meniscus) lens made of crown glass with spherical surfaces of different radii with the reflective coating on the shallower rear surface
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Special
Special
Special
or specials may refer to:Contents1 Music 2 Film and television 3 Other uses 4 See alsoMusic[edit] Special
Special
(album), a 1992 album by Vesta Williams "Special" (Garbage song), 1998 "Special
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Chromatic Aberration
Tilt Spherical aberration Astigmatism Coma Distortion Petzval field curvature Chromatic aberrationPhotographic example showing high quality lens (top) compared to lower quality model exhibiting lateral chromatic aberration (seen as a blur and a rainbow edge in areas of contrast.)In optics, chromatic aberration (abbreviated CA; also called chromatic distortion and spherochromatism) is an effect resulting from dispersion in which there is a failure of a lens to focus all colors to the same convergence point.[1] It occurs because lenses have different refractive indices for different wavelengths of light. The refractive index of transparent materials decreases with increasing wavelength in degrees unique to each.[2] Chromatic aberration
Chromatic aberration
manifests itself as "fringes" of color along boundaries that separate dark and bright parts of the image, because each color in the optical spectrum cannot be focused at a single common point
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Astigmatism (optical Systems)
Tilt Spherical aberration Astigmatism Coma Distortion Petzval field curvature Chromatic aberrationAn optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances. The term comes from the Greek α- (a-) meaning "without" and στίγμα (stigma), "a mark, spot, puncture".[1]Contents1 Forms of astigmatism1.1 Third-order astigmatism 1.2 Astigmatism
Astigmatism
in systems that are not rotationally symmetric1.2.1 Ophthalmic astigmatism 1.2.2 Misaligned or malformed lenses and mirrors 1.2.3 Deliberate astigmatism in optical systems2 See also 3 References 4 External linksForms of astigmatism[edit]Visual astigmatism (not optical)There are two distinct forms of astigmatism
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Coma (optics)
Tilt Spherical aberration Astigmatism Coma Distortion Petzval field curvature Chromatic aberrationComa of a single lensIn optics (especially telescopes), the coma, or comatic aberration, in an optical system refers to aberration inherent to certain optical designs or due to imperfection in the lens or other components that results in off-axis point sources such as stars appearing distorted, appearing to have a tail (coma) like a comet. Specifically, coma is defined as a variation in magnification over the entrance pupil
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Dennis Gabor
Dennis Gabor
Dennis Gabor
CBE FRS[1] (/ˈɡɑːbɔːr, ɡəˈbɔːr/;[2] Hungarian: Gábor Dénes; 5 June 1900 – 9 February 1979) was a Hungarian-British[3] electrical engineer and physicist, most notable for inventing holography, for which he later received the 1971 Nobel Prize in Physics.[4][5][6][7][8][9] Gábor Dénes College in Budapest, Hungary, is named after him in honour of his works.Contents1 Life and career 2 Personal life 3 Awards and honors3.1 In popular culture4 See also 5 References 6 External linksLife and career[edit] Gabor was born as Günszberg Dénes, into a Jewish family in Budapest, Hungary. In 1918, his family converted to Lutheranism.[10] Dennis was the first-born son of Günszberg Bernát and Jakobovits Adél
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Schmidt Camera
A Schmidt camera, also referred to as the Schmidt telescope, is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations. The design was invented by Bernhard Schmidt
Bernhard Schmidt
in 1930. Some notable examples are the Samuel Oschin telescope
Samuel Oschin telescope
(formerly Palomar Schmidt), the UK Schmidt Telescope
UK Schmidt Telescope
and the ESO Schmidt; these provided the major source of all-sky photographic imaging from 1950 until 2000, when electronic detectors took over
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Image-forming Optical System
In optics, an image-forming optical system is a system capable of being used for imaging. The diameter of the aperture of the main objective is a common criterion for comparison among optical systems, such as large telescopes. The two traditional systems are mirror-systems (catoptrics) and lens-systems (dioptrics), although in the late twentieth century, optical fiber was introduced. Catoptrics
Catoptrics
and dioptrics have a focal point, while optical fiber transfers an image from one plane to another without an optical focus. Isaac Newton
Isaac Newton
is reported to have designed what he called a catadioptrical phantasmagoria, which can be interpreted to mean an elaborate structure of both mirrors and lenses. Catoptrics
Catoptrics
and optical fiber have no chromatic aberration, while dioptrics need to have this error corrected
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Ludwig Schupmann
Ludwig Ignaz Schupmann (23 January 1851 in Geseke
Geseke
(Westphalia), Germany
Germany
– 2 October 1920 also in Geseke) was a German professor of architecture and an optical designer. He is principally remembered today for his Medial and Brachymedial telescopes, types of catadioptric reflecting-refracting telescopes with Mangin mirrors that eliminate chromatic aberrations while using common optical glasses. Used in early lunar studies, they are used now in double-star work. The asteroid 5779 Schupmann is named in his honour.† Works[edit] Die Medial-Fernrohre - Eine neue Konstruktion für große astronomische Instrumente, Teubner-Verlag, 1899 External links[edit] Ludwig Schupmann and some Early Medial TelescopesAuthority controlWorldCat Identities VIAF: 14201522 LCCN: n2006071939 GND: 1012217930This article about a German academic is a stub
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Spherical Mirror
A curved mirror is a mirror with a curved reflecting surface. The surface may be either convex (bulging outwards) or concave (bulging inwards). Most curved mirrors have surfaces that are shaped like part of a sphere, but other shapes are sometimes used in optical devices. The most common non-spherical type are parabolic reflectors, found in optical devices such as reflecting telescopes that need to image distant objects, since spherical mirror systems, like spherical lenses, suffer from spherical aberration. Distorting mirrors are used for entertainment
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Argunov–Cassegrain Telescope
The Argunov Cassegrain telescope is a catadioptric telescope design first introduced in 1972 by P. P. Argunov.[1] All optics are spherical, and the classical Cassegrain secondary mirror is replaced by a sub-aperture secondary corrector group consisting of three air-spaced elements, two lenses and a Mangin mirror
Mangin mirror
(the element farthest from the primary mirror). Argunov systems only employ spherical surfaces and avoid the practical difficulties of making and testing aspheres
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Objective (optics)
In optical engineering, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image. Objectives can be a single lens or mirror, or combinations of several optical elements. They are used in microscopes, telescopes, cameras, slide projectors, CD players and many other optical instruments. Objectives are also called object lenses, object glasses, or objective glasses.Contents1 Types1.1 Microscope 1.2 Photography and imaging 1.3 Telescope2 See also 3 ReferencesTypes[edit] Microscope[edit] The objective lens of a microscope is the one at the bottom near the sample. At its simplest, it is a very high-powered magnifying glass, with very short focal length. This is brought very close to the specimen being examined so that the light from the specimen comes to a focus inside the microscope tube
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Klevtsov–Cassegrain Telescope
The Klevtsov– Cassegrain telescope
Cassegrain telescope
is a type of catadioptric Cassegrain telescope
Cassegrain telescope
that uses a spherical primary mirror and a sub-aperture secondary corrector group composed of a small lens and a Mangin mirror.
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Bouwers Meniscus Telescope
Albert A. Bouwers (1893–1972) was a Dutch optical engineer.[1] He is known for developing and working with X-Rays and various optical technologies as a high-level researcher at Philips research labs. He is lesser known for patenting in 1941 a catadioptric meniscus telescope design similar to but slightly predating the Maksutov telescope.[2][3]Contents1 Biography 2 Bouwers meniscus telescope 3 References 4 Further readingBiography[edit] Bouwers was born in the town of Dalen in the Netherlands in 1893.[4] He obtained his Ph.D
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