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Yerkes 41-inch Reflector
Yerkes 41-inch reflector is a 40-inch aperture (101.6 cm) reflecting telescope at the Yerkes Observatory, that was completed in 1968. It is known as the 41 inch to avoid confusion with a 40 inch refractor at the observatory. Optically it is a Ritchey–Chrétien design, and the main mirror uses low expansion glass. The telescope was used as a testbed for an adaptive optics system in the 1990s. History Refracting telescope The glass blanks for what would become Yerkes Great Refractor were made in Paris, France by Mantois and delivered to Alvan Clark & Sons in Massachusetts where they were completed. Reflector telescope In the late 1960s a 40-inch reflecting telescope was added, often called the "41 inch" reflector, and in 2002 it was given a new dome over it. The 41 inch was finished by 1968, with overall installation completed by December 1967 and the optics in 1968. The telescope had a clear aperture of 40 inches, but was often called the "41 inch" so it would not ... [...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 catoptrics, 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 eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yerkes Observatory
Yerkes Observatory ( ) is an astronomical observatory located in Williams Bay, Wisconsin, United States. The observatory was operated by the University of Chicago Department of Astronomy and Astrophysics from its founding in 1897 to 2018. Ownership was transferred to the non-profit Yerkes Future Foundation (YFF) in May 2020, which began restoration and renovation of the historic building and grounds. Re-opening for public tours and programming began May 27, 2022. The observatory, often called "the birthplace of modern astrophysics," was founded in 1892 by astronomer George Ellery Hale and financed by businessman Charles T. Yerkes. It represented a shift in the thinking about observatories, from their being mere housing for telescopes and observers, to the early-20th-century concept of observation equipment integrated with laboratory space for physics and chemistry analysis. The observatory's main dome houses a doublet lens refracting telescope, the largest refractor ever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractor
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens (optics), lens as its objective (optics), objective to form an image (also referred to a dioptrics, dioptric telescope). The refracting telescope design was originally used in spyglasses and astronomy, astronomical telescopes but is also used for long-focus lens, long-focus camera lenses. Although large refracting telescopes were very popular in the second half of the 19th century, for most research purposes, the refracting telescope has been superseded by the reflecting telescope, which allows larger apertures. A refractor's magnification is calculated by dividing the focal length of the objective lens by that of the eyepiece. Refracting telescopes typically have a lens at the front, then a optical train, long tube, then an eyepiece or instrumentation at the rear, where the telescope view comes to focus. Originally, telescopes had an objective of one element, but a century later, tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testbed
A testbed (also spelled test bed) is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies. The term is used across many disciplines to describe experimental research and new product development platforms and environments. They may vary from hands-on prototype development in manufacturing industries such as automobiles (known as " mules"), aircraft engines or systems and to intellectual property refinement in such fields as computer software development shielded from the hazards of testing live. Software development In software development, testbedding is a method of testing a particular module (function, class, or library) in an isolated fashion. It may be used as a proof of concept or when a new module is tested apart from the program/system it will later be added to. A skeleton framework is implemented around the module so that the module behaves as if already part of the larger program. A t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Optics
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. Adaptive optics should not be confused with active optics, which works on a longer timescale to correct the primary mirror geometry. Other methods can achieve resolving power exceeding the limit imposed by atmospheric distortion, such as speckle imaging, aperture synthesis, and lucky imaging, or by moving outside the atmosphere with space telescopes, such as the Hubble Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yerkes 40 Inch Refractor Telescope-1897
Yerkes may refer to: *Yerkes (surname), notable people with this surname *Yerkes, Kentucky *Yerkes, Pennsylvania * Yerkes Observatory, an astronomical observatory of the University of Chicago ** Yerkes luminosity classification of stars ** Yerkes scheme of galaxy morphological classification * Yerkes National Primate Research Center, one of eight national primate research centers funded by the National Institutes of Health, located in Atlanta, Georgia at Emory University * Yerkes–Dodson law, an empirical relationship between arousal and performance first noted by Robert M. Yerkes and John Dillingham Dodson * 990 Yerkes 990 Yerkes is a main belt asteroid discovered by Belgian-American astronomer George Van Biesbroeck in 1922, and named after the Yerkes Observatory. Photometry (astronomy), Photometric observations of this asteroid collected during 2009 show a ro ..., main belt asteroid * Yerkes (crater), on the moon {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yerkes Observatory Astro4p7
Yerkes may refer to: *Yerkes (surname), notable people with this surname *Yerkes, Kentucky *Yerkes, Pennsylvania * Yerkes Observatory, an astronomical observatory of the University of Chicago ** Yerkes luminosity classification of stars ** Yerkes scheme of galaxy morphological classification * Yerkes National Primate Research Center, one of eight national primate research centers funded by the National Institutes of Health, located in Atlanta, Georgia at Emory University * Yerkes–Dodson law, an empirical relationship between arousal and performance first noted by Robert M. Yerkes and John Dillingham Dodson * 990 Yerkes 990 Yerkes is a main belt asteroid discovered by Belgian-American astronomer George Van Biesbroeck in 1922, and named after the Yerkes Observatory. Photometry (astronomy), Photometric observations of this asteroid collected during 2009 show a ro ..., main belt asteroid * Yerkes (crater), on the moon {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alvan Clark & Sons
Alvan Clark & Sons was an American maker of optics that became famous for crafting lenses for some of the largest refracting telescopes of the 19th and early 20th centuries. Founded in 1846 in Cambridgeport, Massachusetts, by Alvan Clark (1804–1887, a descendant of Cape Cod whalers who started as a portrait painter), and his sons George Bassett Clark (1827–1891) and Alvan Graham Clark (1832–1897). Five times, the firm built the largest refracting telescopes in the world. The Clark firm gained "worldwide fame and distribution", wrote one author on astronomy in 1899. The Dearborn telescope (housed successively at the University of Chicago, Northwestern University and Adler Planetarium) was commissioned in 1856 by the University of Mississippi. The outbreak of the Civil War prevented them from ever taking ownership. As a result, it was being tested in Cambridgeport when Alvan Graham observed Sirius B in 1862. In 1873 they built the objective lens for the ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ritchey–Chrétien Telescope
A Ritchey–Chrétien telescope (RCT or simply RC) is a specialized variant of the Cassegrain telescope that has a hyperbolic primary mirror and a hyperbolic secondary mirror designed to eliminate off-axis optical errors (coma). The RCT has a wider field of view free of optical errors compared to a more traditional reflecting telescope configuration. Since the mid 20th century, a majority of large professional research telescopes have been Ritchey–Chrétien configurations; some well-known examples are the Hubble Space Telescope, the Keck telescopes and the ESO Very Large Telescope. History The Ritchey–Chrétien telescope was invented in the early 1910s by American astronomer George Willis Ritchey and French astronomer Henri Chrétien. Ritchey constructed the first successful RCT, which had an aperture diameter of in 1927 (e.g. Ritchey 24-inch reflector). The second RCT was a instrument constructed by Ritchey for the United States Naval Observatory; that telescope is st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cer-Vit
Cer-vit is a family of glass-ceramic materials that were invented by Owens Illinois in the mid-1960s. Its principle ingredients are the oxides of lithium, aluminum and silicon. It is melted to form a glass which is then heat treated to nucleate and crystallize it into a material that is more than 90% microscopic crystals. Its formulation and heat treatment can be modified to produce a variety of material properties. One form is a material that is transparent and has a near zero thermal expansion. Its transparency is because the microscopic crystals are smaller than the wave length of light and are transparent, and its low thermal expansion is because they have a spodumene structure. This material (Cer-Vit C 101) was used to form large mirror blanks (158 inches in diameter) that were used in telescopes in several places, including South America, France and Australia. Owens Illinois ceased production of C101 in 1978. In addition, Cer-Vit materials were used to make stove tops, cook wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
