Special Astrophysical Observatory of the Russian Academy of Science
January 21, 2023
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The BTA-6 (Bolshoi Teleskop Altazimutalny; Большой Телескоп Альтазимутальный, or Large Altazimuth Telescope), with first light in 1975, was for several years the world's largest single primary mirror optical reflecting telescope. The BTA-6's primary mirror has a diameter of 6 metres (236 inches) and is housed in a 48 m (157.5 ft) diameter dome at an altitude of 2,070 m (6,791 ft). It held the record from its completion until 1993, when it was surpassed by the Keck 1 telescope, Hawaii. Telescopes of comparable or larger size have subsequently employed flexible or segmented mirrors, and the BTA-6 remained the world's largest rigid-mirror telescope until the advent of spin-casting technology (which produced, for example, the single 8.4-meter primary mirror of the Large Binocular Telescope in the late 1990s). Its altazimuth mount dictates the need for a field derotation mechanism to maintain the orientation of the field of view.
Initial results were disappointing due to cracking of the first borosilicate mirror, which was replaced in 1978. The large housing dome and massive 42 tonne mirror make it difficult to maintain the telescope at a suitable constant temperature during observing sessions. Atmospheric turbulence caused by windflow over the nearby Caucasus peaks can lead to poor seeing at the site, and observations with an angular resolution better than an arcsecond are rare. Despite these shortcomings, the BTA-6 remains a significant instrument, able to image objects as faint as the 26th magnitude.
The 1-meter Zeiss-1000 and the 60-centimeter Zeiss behind it
Other optical telescopes
Along with the BTA-6, the SAO operates two smaller telescopes at the BTA site, both built by Carl Zeiss AG. Both instruments are used in support of BTA-6 programs, as well as independent observation runs. On the advice of the SAO, programs originally booked for the BTA-6 can be moved to these telescopes, which takes up about 10% of their time.[1]
The larger instrument, the 1 m Zeiss-1000, is located a few hundred meters from BTA-6 in its own building, which consists of a series of offices surrounding the main cylindrical instrument building with the dome on top. First light on the Zeiss-1000 was in 1990, and the installation, including additional instrumentation, was fully completed in 1993.
In 1994 they were joined by a 60 cm Zeiss instrument, formerly part of the Kazan State University's observatory. This is located only a few tens of meters from the Zeiss-1000, in a much simpler building consisting only of the dome and supporting masonry walls.
The RATAN-600 radio telescope (Russian: РАТАН-600 – РАдио Телескоп Академии Наук, or the Academy of Science Radio Telescope), which consists of a 576 m diameter circle of rectangular radio reflectors, is also based at the observatory at an altitude of 970 m. (Coordinates 43°49′34.20″N41°35′12.06″E / 43.8261667°N 41.5866833°E / 43.8261667; 41.5866833.) Each of the 895 2×7.4 m reflectors can be pointed towards a central conical secondary mirror, or to one of five parabolic cylinders. Each reflector is combined with an instrumentation cabin containing various receivers and instruments. The overall effect is that of a partially steerable antenna with the resolving power of a 600 m diameter dish (when using the central conical receiver), making it the world's largest diameter individual radio telescope.
Two-mirror system: An sector of the ring focuses waves to a cylindrical secondary mirror and further onto the receivers
Three-mirror system: The linear plane mirror reflects the waves to the south sector of the ring, which in turn focuses on a cylindrical secondary and onto the receivers (Periscope mirror of Kraus-type system)
Entire ring: For observations near the zenith the entire ring can be used, together with the conical secondary mirror and its receivers
Independent observations at various discrete azimuths are possible simultaneously: For this a sector of the ring is used with one of the secondary mirror and receiver units, the later which can be positioned on railway tracks – meanwhile another sector in conjunction with another secondary mirror can be used for an independent observation. At a wavelength of 8 cm, the effective collecting area of the entire ring is 1,000 square metres (11,000 sq ft) with a resolving power in the horizontal plane of 1 arcminute.
The RATAN-600 is primarily operated as a transit telescope, in which the rotation of the earth is used to sweep the telescope focus across the subject of observation. Radio frequency observations can be made in the frequency band 610 MHz to 30 GHz, though primarily in the centimetric waveband, with an angular resolution of up to 2 arcseconds. Observation of the Sun at radio wavelengths, in particular of the solar corona, has been a long-standing focus of the RATAN-600's scientific programme. It has also contributed to radio observation for the SETI project. The RATAN-600 has not been dogged by the technical problems of the neighbouring BTA-6, and has generally been in high demand since its first operations in mid-1974.
^The RATAN-600 Radio Telescope - Russian Academy of Science, Special Astrophysical Observatory
References and further reading
Parijskij, N & Korol'kov, D (1987). "Experiment Cold: The first deep sky survey with the RATAN-600 radio telescope". Astrophysics and Space Physics Review. 5: 39–179. Bibcode:1987ASPRv...5...39P.
Ioannisiani BK; Neplokhov EM; Kopylov IM; Rylov VS; Snezhko LI (1982). "The Zelenchuk 6M telescope (BTA) of the USSR Academy of Sciences". ASSL Vol. 92: IAU Colloq. 67. 92: 3–10. Bibcode:1982ASSL...92....3I. doi:10.1007/978-94-009-7787-7_1.
External links
SAO homepage (English and Russian)
BTA-6 webcam
Bolshoi Teleskop Azimutalnyi, by Bill Keel
Satellite photo of RATAN-600 on Google Maps, centered on the centre of the telescope
Satellite photo of BTA-6 on Google Maps, centered on the telescope
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January 21, 2023
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This article relies largely or entirely on a single source Relevant discussion may be found on the talk page Please help improve this article by introducing citations to additional sources Find sources Special Astrophysical Observatory of the Russian Academy of Science news newspapers books scholar JSTOR February 2016 The Special Astrophysical Observatory of the Russian Academy of Science SAO RAS Russian Specialnaya Astrofizicheskaya Observatoriya is an astronomical observatory set up in 1966 in the USSR and now operated by the Russian Academy of Sciences Based in the Bolshoi Zelenchuk Valley of the Greater Caucasus near the village of Nizhny Arkhyz the observatory houses the BTA 6 and RATAN 600 an optical and radio telescope respectively The two instruments are about 20 km 12 mi apart Special Astrophysical Observatory of the Russian Academy of ScienceAlternative namesSpecial Astrophysical ObservatoryObservatory code115 LocationKarachay Cherkessia RussiaCoordinates43 38 49 N 41 26 26 E 43 646825 N 41 440447 E 43 646825 41 440447 Coordinates 43 38 49 N 41 26 26 E 43 646825 N 41 440447 E 43 646825 41 440447Websitewww wbr sao wbr ruTelescopesBTA 6RATAN 600 Location of Special Astrophysical Observatory of the Russian Academy of Science Related media on Commons edit on Wikidata Contents 1 BTA 6 optical telescope 2 Other optical telescopes 3 RATAN 600 radio telescope 4 See also 5 References 6 References and further reading 7 External linksBTA 6 optical telescope Edit BTA 6 as seen from in front of the main entrance Main article BTA 6 The BTA 6 Bolshoi Teleskop Altazimutalny Bolshoj Teleskop Altazimutalnyj or Large Altazimuth Telescope with first light in 1975 was for several years the world s largest single primary mirror optical reflecting telescope The BTA 6 s primary mirror has a diameter of 6 metres 236 inches and is housed in a 48 m 157 5 ft diameter dome at an altitude of 2 070 m 6 791 ft It held the record from its completion until 1993 when it was surpassed by the Keck 1 telescope Hawaii Telescopes of comparable or larger size have subsequently employed flexible or segmented mirrors and the BTA 6 remained the world s largest rigid mirror telescope until the advent of spin casting technology which produced for example the single 8 4 meter primary mirror of the Large Binocular Telescope in the late 1990s Its altazimuth mount dictates the need for a field derotation mechanism to maintain the orientation of the field of view Initial results were disappointing due to cracking of the first borosilicate mirror which was replaced in 1978 The large housing dome and massive 42 tonne mirror make it difficult to maintain the telescope at a suitable constant temperature during observing sessions Atmospheric turbulence caused by windflow over the nearby Caucasus peaks can lead to poor seeing at the site and observations with an angular resolution better than an arcsecond are rare Despite these shortcomings the BTA 6 remains a significant instrument able to image objects as faint as the 26th magnitude The 1 meter Zeiss 1000 and the 60 centimeter Zeiss behind itOther optical telescopes EditAlong with the BTA 6 the SAO operates two smaller telescopes at the BTA site both built by Carl Zeiss AG Both instruments are used in support of BTA 6 programs as well as independent observation runs On the advice of the SAO programs originally booked for the BTA 6 can be moved to these telescopes which takes up about 10 of their time 1 The larger instrument the 1 m Zeiss 1000 is located a few hundred meters from BTA 6 in its own building which consists of a series of offices surrounding the main cylindrical instrument building with the dome on top First light on the Zeiss 1000 was in 1990 and the installation including additional instrumentation was fully completed in 1993 In 1994 they were joined by a 60 cm Zeiss instrument formerly part of the Kazan State University s observatory This is located only a few tens of meters from the Zeiss 1000 in a much simpler building consisting only of the dome and supporting masonry walls RATAN 600 radio telescope EditMain article RATAN 600 The RATAN 600 Radio Telescope The RATAN 600 radio telescope Russian RATAN 600 RAdio Teleskop Akademii Nauk or the Academy of Science Radio Telescope which consists of a 576 m diameter circle of rectangular radio reflectors is also based at the observatory at an altitude of 970 m Coordinates 43 49 34 20 N 41 35 12 06 E 43 8261667 N 41 5866833 E 43 8261667 41 5866833 Each of the 895 2 7 4 m reflectors can be pointed towards a central conical secondary mirror or to one of five parabolic cylinders Each reflector is combined with an instrumentation cabin containing various receivers and instruments The overall effect is that of a partially steerable antenna with the resolving power of a 600 m diameter dish when using the central conical receiver making it the world s largest diameter individual radio telescope The telescope can operate in three modes 2 Two mirror system An sector of the ring focuses waves to a cylindrical secondary mirror and further onto the receivers Three mirror system The linear plane mirror reflects the waves to the south sector of the ring which in turn focuses on a cylindrical secondary and onto the receivers Periscope mirror of Kraus type system Entire ring For observations near the zenith the entire ring can be used together with the conical secondary mirror and its receiversIndependent observations at various discrete azimuths are possible simultaneously For this a sector of the ring is used with one of the secondary mirror and receiver units the later which can be positioned on railway tracks meanwhile another sector in conjunction with another secondary mirror can be used for an independent observation At a wavelength of 8 cm the effective collecting area of the entire ring is 1 000 square metres 11 000 sq ft with a resolving power in the horizontal plane of 1 arcminute The RATAN 600 is primarily operated as a transit telescope in which the rotation of the earth is used to sweep the telescope focus across the subject of observation Radio frequency observations can be made in the frequency band 610 MHz to 30 GHz though primarily in the centimetric waveband with an angular resolution of up to 2 arcseconds Observation of the Sun at radio wavelengths in particular of the solar corona has been a long standing focus of the RATAN 600 s scientific programme It has also contributed to radio observation for the SETI project The RATAN 600 has not been dogged by the technical problems of the neighbouring BTA 6 and has generally been in high demand since its first operations in mid 1974 See also EditList of largest optical reflecting telescopes List of radio telescopesReferences Edit Small telescopes The RATAN 600 Radio Telescope Russian Academy of Science Special Astrophysical ObservatoryReferences and further reading EditParijskij N amp Korol kov D 1987 Experiment Cold The first deep sky survey with the RATAN 600 radio telescope Astrophysics and Space Physics Review 5 39 179 Bibcode 1987ASPRv 5 39P Ioannisiani BK Neplokhov EM Kopylov IM Rylov VS Snezhko LI 1982 The Zelenchuk 6M telescope BTA of the USSR Academy of Sciences ASSL Vol 92 IAU Colloq 67 92 3 10 Bibcode 1982ASSL 92 3I doi 10 1007 978 94 009 7787 7 1 External links EditSAO homepage English and Russian BTA 6 webcam Bolshoi Teleskop Azimutalnyi by Bill Keel Satellite photo of RATAN 600 on Google Maps centered on the centre of the telescope Satellite photo of BTA 6 on Google Maps centered on the telescope Wikimedia Commons has media related to Special Astrophysical Observatory of the Russian Academy of Science Retrieved from https en wikipedia org w index php title Special Astrophysical Observatory of the Russian Academy of Science amp oldid 1016668426, wikipedia, wiki, book, books, library,
