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Basically, the catadioptric telescope is just one of the 3 main types of the optical telescopes.The other 2 main types of optical telescopes are the refracting telescopes and the reflecting telescopes.
Ebba Hoeger
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When was the catadioptric telescope invented?
Basically, the catadioptric telescope is just one of the 3 main types of the optical telescopes.The other 2 main types of optical telescopes are the refracting telescopes and the reflecting telescopes.
Who did it the catadioptric telescope?
Early catadioptric systemsCatadioptric combinations have been used in many early optical systems. In the 1820s, Augustin-Jean Fresnel developed several catadioptric lighthouse reflectors.[1]Léon Foucault developed a catadioptric microscope 1859 to counteract aberrations of using a lens to image objects at high power.[2]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 surfaces of the reflector have different radii to correct the aberration of the spherical mirror. Light passes through the glass twice, making the over all system act like a triplet lens.[3]Mangin mirrors were used in searchlights where they produced a nearly true parallel beam. Many Catadioptric telescopes use negative lenses with a reflective coating on the backside that are referred to as "Mangin mirrors", although they are not single element objectives like the original Mangin and some even predate the Mangin's invention.[4][edit]Catadioptric telescopesCatadioptric telescopes are optical telescopes that combine specifically shaped mirrors and lenses to form an image. This is usually done so that the telescope can have an overall greater degree of error correction than their all lens or mirror counterparts with a consequently wider aberration free field of view. Their designs can have simple all spherical surfaces and can take advantage of a folded optical path that reduces the mass of the telescope, making them easier to manufacture. Many types employ "correctors", a lens or curved mirror in a combined image-forming optical system so that the reflective or refractive element can correct the aberrations produced by its counterpart.[edit]Catadioptric dialytesCatadioptric dialytes are the earliest type of catadioptric telescope. They consist of a single element refractorobjectivecombined with a silver backed negative lens (similar to a Mangin mirror). The first of these was the Hamiltonian telescope patented by W. F. Hamilton in 1814. The Schupmann medial telescope designed by German optician Ludwig Schupmann near the end of the 19th century placed the catadioptric mirror beyond the focus of the refractor primary and added a 3rd correcting/focusing lens to the system.[edit]Full aperture correctorsThere are several telescope designs that take advantage of placing full diameter lens (commonly called a "corrector plate") in front of a spherical primary mirror. These designs take advantage of all the surfaces being "spherically symmetrical"[5]and were originally invented to create optical systems with very fast focal ratios (wide fields of view) with little coma or astigmatism for use as astrographic cameras. They work by combining a spherical mirror's ability to reflect light back to the same point with a large lens at the front of the system (a corrector) that slightly bends the incoming light, allowing the spherical mirror to image objects at infinity. Some of these designs have been adapted to create compact long focal length catadioptric cassegrains.[edit]The Schmidt corrector plateThe Schmidt corrector, the first full diameter corrector plate, was used in Bernhard Schmidt's 1931 Schmidt camera. The Schmidt camera is a wide field photographic telescope, with the corrector plate at the center of curvature of the primary mirror, producing an image at a focus inside the tube assembly where a curved film plate or detector is mounted. The relatively thin and lightweight corrector allows Schmidt cameras to be constructed in diameters up to 1.3 m. The corrector's complex shape takes several processes to make, starting with a flat piece of optical glass, placing a vacuum on one side of it to curve the whole piece, then grinding and polishing the other side flat to achieve the exact shape required to correct the spherical aberration caused by the primary mirror. The design has lent itself to many Schmidt variants.Popular sub-types Light path in a Schmidt-CassegrainSchmidt-Cassegrain telescopes are one of the most popular commercial designs on the amateur astronomical market,[6]having been mass-produced since the 1960s. The design replaces the Schmidt Camera film holder with a Cassegrain secondary mirror making a folded optical path with a long focal length and a narrow field of view.[edit]The meniscus corrector shellThe idea of replacing the complicated Schmidt corrector plate with an easy to manufacture full aperture spherical meniscus lens (a meniscus corrector shell) to create a wide field telescope occurred to at least 4 optical designers in early 1940s war-torn Europe, including Albert Bouwers (1940), Dmitri Dmitrievich Maksutov (1941), K. Penning, andDennis Gabor (1941).[7][8]Wartime secrecy kept these inventors from knowing about each others' designs, leading to each being an independent invention. Albert Bouwers built a prototype meniscus telescope in August 1940 and patented it in February 1941. It used a spherically concentric meniscus and was only suitable as a monochromatic astronomical camera. In a later design he added a cemented doublet to correct chromatic aberration. Dmitri Maksutov built a prototype for a similar type of meniscus telescope, the Maksutov telescope, in October 1941 and patented it in November of that same year.[9]His design corrected spherical and chromatic aberrations by placing a weak negative shaped meniscus corrector closer to the primary mirror.Popular sub-types Light path in a meniscus telescope (Maksutov-Cassegrain)Maksutov-Cassegrain telescopes are the most commonly seen design that uses a meniscus corrector, a variant of the Maksutov telescope. It has a silvered "spot" secondary on the corrector making a long focal length but compact (folded optical path) telescope with a narrow field of view. This design idea appeared in Dmitri Maksutov's 1941 notes and was originally developed in commercial designs by Lawrence Braymer (Questar, 1954), and John Gregory (1955 patent[10]). The combination of the corrector with the silvered secondary spot makes Maksutov-Cassegrains low maintenance and ruggedized since they can be air sealed and fixed in alignment (collimation).[edit]Sub-aperture correctorsLight path in a Argunov Cassegrain telescopeIn sub-aperture corrector designs, the corrector elements are usually at the focus of a much larger objective. These elements can be both lenses and mirrors, but since multiple surfaces are involved, achieving good aberration correction in these systems can be very complex.[4]Examples of sub-aperture corrector catadioptric telescopes include the Argunov-Cassegrain telescope, the Klevtsov-Cassegrain telescope and sub-aperture corrector Maksutovs, which use as a "secondary mirror" an optical group consisting of lens elements and sometimes mirrors designed to correct abberarion.[edit]Photographic catadioptric lensesExample of a catadioptric lens using rear surfaced "mangin mirrors" (Minolta RF Rokkor-X 250mm f/5.6)Various types of catadioptric systems are also used in camera lensesknown alternatively as catadioptric lenses(CATs), reflex lenses, or mirror lenses. These lenses use some form of the cassegrain design which greatly reduces the physical length of the optical assembly, partly by folding the optical path, but mostly through the telephoto effect of the convex secondary mirror which multiplies the focal length many times (up to 4 to 5 times).[11]This creates lenses with focal lengths from 250 mm up to and beyond 1000 mm that are much shorter and compact than theirlong focus or telephoto counterparts. Moreover, chromatic aberration, a major problem with long refractive lenses, and off-axis aberration, a major problem with reflective telescopes, is almost completely eliminated by the catadioptric system, making the image they produce suitable to fill the large focal plane of a camera.An example of 'iris blur' or bokeh produced by a catadioptric lens, behind an in-focus light.Catadioptric lenses do, however, have several drawbacks. The fact that they have a central obstruction means they cannot use an adjustable diaphragm to control light transmission.[12]This means the lens's F-number value is fixed to the overall designed focal ratio of the optical system (the diameter of the primary mirror divided into the focal length). Exposure is usually adjusted by the placement of neutral density filters on the front or rear of the lens. Their modulation transfer function shows low contrast at low spatial frequencies. Finally, their most salient characteristic is the annular shape of defocused areas of the image, giving a doughnut-shaped 'iris blur' or bokeh, caused by the shape of the entrance pupil.Several companies made catadioptric lenses throughout the later part of the 20th century. Nikon (under the Mirror-Nikkorand later Reflex-Nikkornames) and Canonboth offered several designs, such as 500 mm 1:8 and 1000 mm 1:11. Smaller companies such as f.e. Tamron, Samyang, Vivitar, and Opteka also offered several versions, with the three latter of these brands still actively producing a number of catadioptric lenses for use in modern system cameras. Of the major manufacturers, however, currently only Sony (formerly Minolta) offers a 500 mm catadioptric lens for their Alpha range of cameras. The Sony lens has the distinction of being the only reflex lens manufactured by a major brand to feature auto-focus (aside from the identical Minolta-manufactured lens that preceded Sony's production).
What type of telescope is hubble space telescope?
It is a reflecting telescope
What are the kinds of telescope?
Optical TelescopesReflecting (mirrors) Refracting (lenses)Catadioptric (combination of lenses and mirrors)Radio TelescopesFixed antennae Phased arrayMovable dishX-ray TelescopesGamma ray Telescopes
What is an artificial telescope?
an artificial telescope is a telescope that is man made by people from NASA or anyone who can make a telescope
Why are telescope eyepieces an important part of any visual telescope?
Telescope eyepieces are important of any visual telescope. It is the main part of the telescope and is what determines how the object will look like through the telescope.
How do you spell telescope?
Telescope.
What type on telescope in the south African large telescope?
it is a reflector telescope
Is theHubble telescope is an optical telescope?
The Hubble Space Telescope has a number of instruments, but the primary one is an optical telescope.
Why did Isaac Newton invent the telescope?
Newton did not invent the telescope, he invented the reflecting telescope. The reflecting telescope was a major improvement over the distorting refracting telescope.
Did Isacc Newton create the telescope?
No. A Dutchman created a refractive telescope. Newton improved the telescope by creating the Reflective Telescope.
What should you look for when buying a telescope?
Quality of the Lenses and/or mirrors first. Coatings put on those mirrors/lenses. Telescope design - Refractor, Reflector, Catadioptric (Combination of lenses and mirrors. What do you want to observe in the sky? - Planets? (The highest quality refractor is the best but most expensive. Stars and Nebulae? you want to get a large diameter reflector to gather as much light as possible. Do you want a compromise in design quality choose a catadioptric. You want a good and sturdy mount (one with mass). many telescopes come with computer controls to make set up and locating objects easier. Telescopes and their uses are simple and very to extremely complicated at the same time. Quality = costs money, Quality + bigger size = often exponentially more money and weight The two leading telescope brands are Meade and Celestron. Perhaps if one wants the best compromise of resolution with light gathering capacity and portability at the lowest price you would choose a catadioptric which is probably why these are the most popular selling telescopes. If someone is a beginner they might want to choose a telescope 4" or smaller. intermediate 5" to 8". advanced - 8" to 10" to 20" etc........ There is an "Astronomical" amount of things one could consider in acquiring a telescope and Astronomy is a hobby that can entertain for a lifetime. One can get a very good feel for astronomy and its potential from a good quality 4" or 5" telescope for a beginner and would be a good choice for such at a reasonable price. This would help you decide if you liked astronomy. There is a lot more to learn than is what I stated here but these are good fundamentals. It is often stated that the best telescope is the one that's used the most. Meaning that if you buy a big expensive telescope and have to bring it in and outside it may not get used often, but a smaller one that is easily brought in and out may get a lot more use and satisfaction out of. I am talking with over twenty years experience and I know I will never run out of things to do with my telescopes. Oh, and did you want to take pictures? Sorry that's for another book.
