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A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, and brick.
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.
Glass-ceramics are polycrystalline materials produced through controlled crystallization of base glass, producing a fine uniform dispersion of crystals throughout the bulk material. Crystallization is accomplished by subjecting suitable glasses to a carefully regulated heat treatment schedule, resulting in the nucleation and growth of crystal phases. In many cases, the crystallization process can proceed to near completion, but in a small proportion of processes, the residual glass phase often remains.
Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, in contrast with theoretical astronomy, which is mainly concerned with calculating the measurable implications of physical models. It is the practice and study of observing celestial objects with the use of telescopes and other astronomical instruments.
The VLT Survey Telescope (VST) is a telescope located at ESO's Paranal Observatory in the Atacama Desert of northern Chile. It is housed in an enclosure immediately adjacent to the four Very Large Telescope (VLT) Unit Telescopes on the summit of Cerro Paranal. The VST is a wide-field survey telescope with a field of view twice as broad as the full Moon. It is the largest telescope in the world designed to exclusively survey the sky in visible light.
The Stratospheric Observatory For Infrared Astronomy (SOFIA) was an 80/20 joint project of NASA and the German Aerospace Center (DLR) to construct and maintain an airborne observatory. NASA awarded the contract for the development of the aircraft, operation of the observatory and management of the American part of the project to the Universities Space Research Association (USRA) in 1996. The DSI managed the German parts of the project which were primarily science- and telescope-related. SOFIA's telescope saw first light on May 26, 2010. SOFIA was the successor to the Kuiper Airborne Observatory. During 10-hour, overnight flights, it observed celestial magnetic fields, star-forming regions, comets, nebulae, and the Galactic Center.
The Hale Telescope is a 200-inch (5.1 m), f/3.3 reflecting telescope at the Palomar Observatory in San Diego County, California, US, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation in 1928, he orchestrated the planning, design, and construction of the observatory, but with the project ending up taking 20 years he did not live to see its commissioning. The Hale was groundbreaking for its time, with double the diameter of the second-largest telescope, and pioneered many new technologies in telescope mount design and in the design and fabrication of its large aluminum coated "honeycomb" low thermal expansion Pyrex mirror. It was completed in 1949 and is still in active use.
Many ceramic materials, both glassy and crystalline, have found use as optically transparent materials in various forms from bulk solid-state components to high surface area forms such as thin films, coatings, and fibers. Such devices have found widespread use for various applications in the electro-optical field including: optical fibers for guided lightwave transmission, optical switches, laser amplifiers and lenses, hosts for solid-state lasers and optical window materials for gas lasers, and infrared (IR) heat seeking devices for missile guidance systems and IR night vision.
The MDM Observatory is an optical astronomical observatory located adjacent to Kitt Peak National Observatory on Kitt Peak, west of Tucson, Arizona, in the United States. It is owned and operated by the University of Michigan, Dartmouth College, Ohio State University, Columbia University, and Ohio University. The Massachusetts Institute of Technology (MIT) was also part of the operating consortium in the past.
The BTA-6 is a 6-metre (20 ft) aperture optical telescope at the Special Astrophysical Observatory located in the Zelenchuksky District of Karachay-Cherkessia on the north side of the Caucasus Mountains in southern Russia.
Highland Road Park Observatory or Baton Rouge Observatory is an astronomical observatory jointly operated by Louisiana State University's astronomy department, Baton Rouge Astronomical Society, and The Recreation & Park Commission for the Parish of East Baton Rouge. It is in Baton Rouge, in the U.S. state of Louisiana, in Highland Road Park.
Mount Lemmon Observatory (MLO), also known as the Mount Lemmon Infrared Observatory, is an astronomical observatory located on Mount Lemmon in the Santa Catalina Mountains approximately 28 kilometers (17 mi) northeast of Tucson, Arizona (US). The site in the Coronado National Forest is used with special permission from the U.S. Forest Service by the University of Arizona's Steward Observatory, and contains a number of independently managed telescopes.
A glass-ceramic-to-metal seal is a type of mechanical seal which binds glass-ceramic and metal surfaces. They are related to glass-to-metal seals, and like them are hermetic (airtight).
Zerodur, a registered trademark of Schott AG, is a lithium-aluminosilicate glass-ceramic produced by Schott AG since 1968. It has been used for a number of very large telescope mirrors including GTC, Keck I, Keck II, and SOFIA, as well as some smaller telescopes. With its very low coefficient of thermal expansion (CTE) it can be used to produce mirrors that retain acceptable figures in extremely cold environments such as deep space. Although it has advantages for applications requiring a coefficient of thermal expansion less than that of borosilicate glass, it remains very expensive as compared to borosilicate. The tight tolerance on CTE, ±0.007×10−6 K−1, allows for its use in high-precision applications.
Ultra low expansion glass (ULE) is a registered trademark of Corning Incorporated. ULE has a very low coefficient of thermal expansion and contains as components silica and less than 10% titanium dioxide. Such high resistance to thermal expansion makes it very resistant to high temperature thermal shock. ULE has been made by Corning since the 1960s, but is still very important to current applications.
Solid is one of the four fundamental states of matter along with liquid, gas, and plasma. The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural rigidity and resistance to a force applied to the surface. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire available volume like a gas. The atoms in a solid are bound to each other, either in a regular geometric lattice, or irregularly. Solids cannot be compressed with little pressure whereas gases can be compressed with little pressure because the molecules in a gas are loosely packed.
Pyroceram is the original glass-ceramic material developed and trademarked by Corning Glass in the 1950s. Pyroceram is an opaque, white, glass material, commonly used in kitchenware, glass stove tops, wood stove doors, etc.. It has high heat tolerance and low thermal expansion.
Sitall is a crystalline glass-ceramic with ultra-low coefficient of thermal expansion (CTE). It was originally manufactured in the former Soviet Union and was used in the making of primary mirrors for the Russian Maksutov telescopes, but since dissolution has diminished in quality. It has a CTE of only 0 ± 1.5×10−7 °C−1 in the temperature range −60 to 60 °C, placing it in a small group of transparent materials with low CTE such as Vycor, Zerodur, Cer‑Vit and fused quartz.
Visions is a brand of transparent stove top cookware created by Corning France and introduced to Europe during the late 1970s. In 1983, it was introduced in the United States and became the number one selling cookware set for a number of years. Visions is made of a transparent material belonging to the Pyroceram family of glass-ceramics. It is one of the few cookware lines that can be used on the range, in the oven, and under a broiler. It will withstand heat up to 850 °C (1,560 °F) with thermal traits similar to Corning Ware plus improved resistance to staining and the detrimental effects of acids and detergents. Visions is sold worldwide by Instant Brands.
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.
References
- ↑ Hubbard, W. B. (1978). "University of Arizona, Department of Planetary Sciences/Lunar and Planetary Laboratory, Tucson, Arizona. Report from 1 October 1976 to 30 September 1977". Bulletin of the Astronomical Society. 10: 16. Bibcode:1978BAAS...10...16H.
- ↑ Ney, E. P. (1975). "University of Minnesota, Minneapolis, Minnesota. Observatory report". Bulletin of the Astronomical Society. 7: 150. Bibcode:1975BAAS....7..150N.
- ↑ "Asteroid 2011 AG5 - A Reality Check (NASA)". Archived from the original on 2021-04-16. Retrieved 2014-08-09.
