CHARA array

The CHARA Array is an astronomical optical interferometer operated by The Center for High Angular Resolution Astronomy (CHARA) at Georgia State University. CHARA is the World's highest angular resolution telescope at infrared wavelengths. The array will eventually have six 1-metre diameter telescopes, making it one of the most powerful imaging interferometers in the world. CHARA array - Related pages. Similar imaging interferometers include COAST, NPOI and more recently VLTI/AMB ...

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A telescope (from the Greek tele = 'far' and skopein = 'to look or see'; teleskopos = 'far-seeing') is an optical tool which gathers and focuses electromagnetic radiation. Telescopes increase the apparent angular size of distant objects, as well as their apparent brightness. Telescopes are used for astronomy and in many non-astronomical instruments including theodolites, transits, spotting scopes, monoculars, binoculars, camera lenses and spyglasses. The word "telescope" usually refers to optical telescopes, but there are telescopes for mo ...

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• Telescope - Types
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• Telescope - Research telescopes
• Telescope - Imperfect images
• Telescope - The five Seidel aberrations
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The Very Large Telescope Project (VLT) consists of a system of four separate optical telescopes (the Antu telescope, the Kueyen telescope, the Melipal telescope, and the Yepun telescope) organized in an array formation. Each telescope has an 8.2 m aperture. The project is organized by the European Southern Observatory. VLT is located at the Paranal Observatory on Cerro Paranal, a 2,635 m high mountain in the Atacama desert in northern Chile. Very Large Telescope - General informa ...

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• Very Large Telescope - General information
• Very Large Telescope - Interferometry and the VLTI

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The VLT consists of a cluster of four large (8.2 meter diameter) telescopes, and an interferometer (VLTI) which is used to resolve fine features. The interferometer will include a set of 1.8 meter diameter telescopes dedicated to interferometric observations. The 8.2 meter telescopes have been named after the names of some astronomical objects in the local Mapuche language: Antu (The Sun), Kueyen ...

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Very Large Telescope, Very Large Telescope - General information, Very Large Telescope - Interferometry and the VLTI

Read more here: » Very Large Telescope: Encyclopedia II - Very Large Telescope - General information

Later, optical interferometry was used on the Mount Wilson Observatory's reflector telescope in order to measure the diameters of stars. This method was extended to measurements using separated telescopes by Johnson, Betz and Towns (1974) in the infrared and by Labeyrie (1975) in the visible. The red giant star Betelgeuse was among the first to have its diameter determined in this way. In the 1980s the aperture synthesis technique was extended to visible light and infrared astronomy by the Cavendish Astrophysics Group, providing the first ve ...

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Optical interferometry, Optical interferometry - Astronomical optical interferometry, Optical interferometry - For further information see, Optical interferometry - The Michelson-Morley experiment, Optical interferometry - Geodetic standard baseline measurements, Optical interferometry - Holography, Optical interferometry - Inertial navigation

Read more here: » Optical interferometry: Encyclopedia II - Optical interferometry - Astronomical optical interferometry

An interferometer works on the principle that two waves that coincide with the same phase will amplify each other while two waves that have opposite phases will cancel each other out. In the beginning, most interferometers used white light sources (e.g., Young's double slit experiment of 1805). Nowadays researchers often use monochromatic light sources like lasers, and even the wave character of matter can be exploited to build interferometers. One of the first examples of matter interferometers were electron interferometers, later fo ...

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Interferometry, Interferometry - Interferometer, Interferometry - Related lists

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The first telescopes may have been Assyrian crystal lenses. Article Though the Visby lenses tentatively suggest that the technology was known to the Arabs and then to the Vikings in the 10th century, credit for assembling the first telescope is usually given to an unknown Dutch spectacle maker in about 1608. Some name that person as Hans Lippershey (c1570-c1619). Even if Lippershey did not make the first one, he publicized it. Galileo Galilei made his own telescope in 1609, calling it at first a perspicillum, and then using the ...

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Telescope, Telescope - History, Telescope - Types, Telescope - Telescope mountings, Telescope - Research telescopes, Telescope - Imperfect images, Telescope - The five Seidel aberrations, Telescope - The chromatic aberrations, Telescope - Famous optical telescopes, Telescope - Related lists

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Most interferometry will be done using 1.8 meter Auxiliary Telescopes (ATs), which will be dedicated to full-time interferometric measurements. The first observations using a pair of ATs were conducted in February 2005, and additional ATs are expected to be installed soon. For interferometric observations on the brightest objects, there is little benefit in using 8 meter telescopes rather than 1.8 meter telescopes. In its interferometric operating mode, the light from the telescopes is reflected off mirrors and directed through tunnel ...

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Very Large Telescope, Very Large Telescope - General information, Very Large Telescope - Interferometry and the VLTI

Read more here: » Very Large Telescope: Encyclopedia II - Very Large Telescope - Interferometry and the VLTI

The telescopes are broadly classified into two main categories. Optical telescopes Radio telescopes The optical telescopes are again divided into two Galilean refracting telescopes Newtonian reflecting telescopes The Galilean or refracting telescopes used refraction property of light. They were made up of lenses. They can be used for both terrestrial as well as astronomical viewing. The Newtonian or reflecting telescopes used reflec ...

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Telescope, Telescope - History, Telescope - Types, Telescope - Telescope mountings, Telescope - Research telescopes, Telescope - Imperfect images, Telescope - The five Seidel aberrations, Telescope - The chromatic aberrations, Telescope - Famous optical telescopes, Telescope - Related lists

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A simple telescope mount is an altitude-azimuth or altazimuth mount. It is similar to that of a surveying transit. A fork rotates in azimuth (in the horizontal plane), and bearings on the tips of the fork allow the telescope to vary in altitude (in a vertical plane). A dobsonian mount is a type of altazimuth mount which has proven to be very popular as it is simple and cheap to make. The major problem with using an altazimuth for astronomy is that both axes must be continuously adjusted to compensate for the Earth ...

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Telescope, Telescope - History, Telescope - Types, Telescope - Telescope mountings, Telescope - Research telescopes, Telescope - Imperfect images, Telescope - The five Seidel aberrations, Telescope - The chromatic aberrations, Telescope - Famous optical telescopes, Telescope - Related lists

Read more here: » Telescope: Encyclopedia II - Telescope - Telescope mountings

A famous use of white light interferometry is the precise measurement of geodetic standard baselines as invented by Yrjö Väisälä. Here, the light path is split in two, and one leg is "folded" between a mirror pair 1 m apart. The other leg bounces once off a mirror 6 m away. Only if the second path is precisely 6 times the first, will fringes be seen. Starting from a standard quartz gauge of 1 m length, it is possible to measure distances up to 864 m by repeated multiplication. Baselines thus established are used to calibrate geodetic distance measurement equipment on, leading to a m ...

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Optical interferometry, Optical interferometry - Astronomical optical interferometry, Optical interferometry - For further information see, Optical interferometry - The Michelson-Morley experiment, Optical interferometry - Geodetic standard baseline measurements, Optical interferometry - Holography, Optical interferometry - Inertial navigation

Read more here: » Optical interferometry: Encyclopedia II - Optical interferometry - Geodetic standard baseline measurements

Most large research telescopes can operate as either a cassegrain telescope (longer focal length, and a narrower field with higher magnification) or newtonian telescope (brighter field). They have a pierced primary, a newtonian focus, and a spider to mount a variety of replaceable secondaries. A new era of telescope making was inaugurated by the MMT, with a mirror composed of six segments synthesizing a mirror of 4.5 metres diameter (this has now been replaced by a single 6.5m mirror). Its example was followed by ...

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Telescope, Telescope - History, Telescope - Types, Telescope - Telescope mountings, Telescope - Research telescopes, Telescope - Imperfect images, Telescope - The five Seidel aberrations, Telescope - The chromatic aberrations, Telescope - Famous optical telescopes, Telescope - Related lists

Read more here: » Telescope: Encyclopedia II - Telescope - Research telescopes