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Catadioptric
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses (dioptrics) and curved mirrors ( catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric", such as surveillance catadioptric sensors. Early catadioptric systems Catadioptric combinations have been used for many early optical systems. In the 1820s, Augustin-Jean Fresnel developed several catadioptric lighthouse reflectors. Léon Foucault developed a catadioptric microscope in 1859 to counteract aberrations of using a lens to image objects at high power. In 1876 a French engineer, A. Mangin, invented what has come to be called the Mangin mirror, a concave glass reflector with the silver surface on the rear side of the glass. The two surface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catadioptric System
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses ( dioptrics) and curved mirrors ( catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, headlamps, early lighthouse focusing systems, optical telescopes, microscopes, and telephoto lenses. Other optical systems that use lenses and mirrors are also referred to as "catadioptric", such as surveillance catadioptric sensors. Early catadioptric systems Catadioptric combinations have been used for many early optical systems. In the 1820s, Augustin-Jean Fresnel developed several catadioptric lighthouse reflectors. Léon Foucault developed a catadioptric microscope in 1859 to counteract aberrations of using a lens to image objects at high power. In 1876 a French engineer, A. Mangin, invented what has come to be called the Mangin mirror, a concave glass reflector with the silver surface on the rear side of the glass. The two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Augustin-Jean Fresnel
Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton's corpuscular theory, from the late 1830s until the end of the 19th century. He is perhaps better known for inventing the catadioptric (reflective/refractive) Fresnel lens and for pioneering the use of "stepped" lenses to extend the visibility of lighthouses, saving countless lives at sea. The simpler dioptric (purely refractive) stepped lens, first proposed by Count Buffon and independently reinvented by Fresnel, is used in screen magnifiers and in condenser lenses for overhead projectors. By expressing Huygens's principle of secondary waves and Young's principle of interference in quantitative terms, and supposing that simple colors consist of sinusoidal waves, Fresnel gave the first satisfactory explanation of diffraction by straight edges, inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 if certain conditions are met. This reflector was invented in 1876 by a French officer Alphonse Mangin as an improved catadioptric reflector for search lights and is also used in other optical devices. Description 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. The spherical aberration normally produced by the simple spherical mirror surface is canceled out by the opposite spherical aberration produced by the light traveling through the negative lens. Since light passes through the glass twice, the overall system acts like a triplet lens. The Mangin mirror was invented in 1876 by a French military engineer named Colonel Alphonse Mangin as a sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflecting Telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter objectives. Almost all of the major telescopes used in astronomy research are reflectors. Many variant forms are in use and some employ extra optical elements to improve image quality or place the image in a mechanically advantageous position. Since reflecting telescopes use mirrors, the design is sometimes referred to as a catoptric telescope. From the time of Newton to the 1800s, the mirror itself was made of metal usually speculum metal. This type included Newton's first designs and even the larges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephoto
A telephoto lens, in photography and cinematography, is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a ''telephoto group'' that extends the light path to create a long-focus lens in a much shorter overall design. The angle of view and other effects of long-focus lenses are the same for telephoto lenses of the same specified focal length. Long-focal-length lenses are often informally referred to as ''telephoto lenses'', although this is technically incorrect: a telephoto lens specifically incorporates the telephoto group. Telephoto lenses are sometimes broken into the further sub-types of short telephoto (85–135 mm in 35 mm film format), medium telephoto: (135–300 mm in 35 mm film format) and super telephoto (over 300 mm in 35 mm film format) . Construction In contrast to a telephoto lens, for any given focal leng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Telescopes
An optical telescope is a telescope that gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electronic image sensors. There are three primary types of optical telescope: * Refracting telescopes, which use lenses and less commonly also prisms (dioptrics) * Reflecting telescopes, which use mirrors ( catoptrics) * Catadioptric telescopes, which combine lenses and mirrors An optical telescope's ability to resolve small details is directly related to the diameter (or aperture) of its objective (the primary lens or mirror that collects and focuses the light), and its light-gathering power is related to the area of the objective. The larger the objective, the more light the telescope collects and the finer detail it resolves. People use optical telescopes (including monoculars and binoculars) for outdoor activities such as observation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Telescope
An optical telescope is a telescope that gathers and focuses light mainly from the visible part of the electromagnetic spectrum, to create a magnified image for direct visual inspection, to make a photograph, or to collect data through electronic image sensors. There are three primary types of optical telescope: * Refracting telescopes, which use lenses and less commonly also prisms ( dioptrics) * Reflecting telescopes, which use mirrors ( catoptrics) * Catadioptric telescopes, which combine lenses and mirrors An optical telescope's ability to resolve small details is directly related to the diameter (or aperture) of its objective (the primary lens or mirror that collects and focuses the light), and its light-gathering power is related to the area of the objective. The larger the objective, the more light the telescope collects and the finer detail it resolves. People use optical telescopes (including monoculars and binoculars) for outdoor activities such as obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catadioptric Sensor
A catadioptric sensor is a visual sensor that contains mirrors (catoptrics) and lenses (dioptrics), a combined catadioptric system. These are panoramic sensors created by pointing a camera A camera is an optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), with a ... at a curved mirror. Image sensors {{Optics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludwig Schupmann
Ludwig Ignaz Schupmann (23 January 1851 in Geseke (Westphalia), 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 An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ... 5779 Schupmann is named in his honour. Works ''Die Medial-Fernrohre - Eine neue Konstruktion für große astronomische Instrumente'', Teubner-Verlag, 1899 External links Ludwig Schupmann and some Early Medial Telescopes 1851 births 1920 deaths Archite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, binoculars, telescopes, cameras, slide projectors, CD players and many other optical instruments. Objectives are also called object lenses, object glasses, or objective glasses. Microscope objectives 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. The objective itself is usually a cylinder containing one or more lenses that are typically made of glass; its function is to collect light from the sample. Magnification One of the most important prope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dialyte Lens
A dialyte lens (sometimes called a ''dialyt'') is a compound lens design that corrects optical aberrations where the lens elements are widely air-spaced. The design is used to save on the amount of glass used for specific elements or where elements can not be cemented because they have dissimilar curvatures. The word ''dialyte'' means "parted", "loose" or "separated". Dialyte telescopes The idea of widely separating the color correcting elements of a lens dates back to W. F. Hamilton's 1814 catadioptric Hamiltonian telescope and Alexander Rogers' 1828 proposals for a ''dialytic refractor''. The goal was to combine a large crown glass objective with a much smaller flint glass downstream to make an achromatic lens since flint glass at that time was very expensive. Dialyte designs were also used in the Schupmann medial telescope designed by in German optician Ludwig Schupmann near the end of the 19th century, in John Wall's 1999 "''Zerochromat''" retrofocally corrected dialytic r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 and dioptrics have a focal point, while optical fiber transfers an image from one plane to another without an optical focus. 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 and optical fiber have no chromatic aberration, while dioptrics need to have this error corrected. Newton believed that such correction was impossible, because he thought the path of the light depended only on its color. In 1757 John Dollond was able to create an achromatised d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
