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Russian Academy of Sciences / Special Astrophysical Observatory

General information

Full Name
Special Astrophysical Observatory (SAO)

Niznyi Arghys, Zelenchuksky District, Karachai-Circassian Republic, 357147, Russia




ISTC Projects


The Special Astrophysical Observatory (SAO) was established in June 1966 as a research institute of the Department of General Physics and Astronomy of the USSR Academy of Science by the decision of the USSR government and the Presidium of the Academy of Science.

The principal instruments of the Observatory are the optical telescope BTA (Big Telescope Azimuth) with the main mirror 6 meters in diameter and the radio telescope RATAN-600 (Radio Telescope of the Academy of Science) with the ring multi-element antenna 600 meters in diameter. The observatory ensures telescope observations under programs approved by the Time Allocation Committee and carries out its own fundamental research in the field of astrophysics.

At present SAO is the only Russian center of ground-based observations of the Universe. The observatory furnishes 80% of observational data in the field of optical and radio astronomy in Russia. The telescopes BTA and RATAN-600 have the common use status allowing a broad integration with the world astronomical community.

The Observatory is located in the Zelenchuk region of Karachai-Cirkassian Republic of Russian Federation. The optical telescope BTA is situated on a slope of the Pastukhov's mountain at the altitude of 2100 m above the sea level. The coordinates of the site: longitude 41o26'30", latitude +43o 39'12". Here there is also a group of smaller 1-m and 0.6-m telescopes. The radio telescope RATAN-600 is mounted at 20 km from the BTA at the southern outskirts of Zelenchukskaya village at the altitude of 970 meters. The laboratory buildings of SAO and the research settlement Nizhnij Arkhyz are erected on the riverside of Bolshoi Zelenchuk in the gorge connecting the Zelenchuk valley with the Alpine Arkhyz.

The observatory research work is performed in 20 laboratories and groups, in the laboratories of St-Petersburg Branch in Pulkovo, in the Department of Informatics and in the Moscow Branch. The SAO's staff is 470 members, 110 persons of them being researchers.


The scientific results obtained by SAO researchers during the last year and offered to Russian Academy of Science are presented briefly here. An archive since 1993 is available (in Russian).

Solar system

– From RATAN-600 observations with a matrix radiometer at a wavelength of 1 cm indications have been found of existence of relativistic electrons in the magnetosphere of Jupiter with energy of about 100 MeV, which demands revision of mechanisms of acceleration of cosmic rays of the solar wind with energy of a few MeV. The longitudinal distribution of radio brightness over the disk of the planet, which is much more homogeneous in comparison with latitudinal, has been obtained for the first time.
– Based on a new method of multiazimuthal observations at RATAN-600 in the decimeter range direct evidence of existence of long-duration non-thermal radiation in the magnetosphere of the solar active region (halo) has been found and plasma mechanisms explaining their nature have been suggested. In co-operation with SPbSU and Beijing Observatory (China).


– The longitudinal magnetic field of the young star of T Taurus (150 + 40 G) an order of magnitude weaker than expected has been first measured at the 6 m telescope. It is shown that the magnetic field does not play an important part in the formation of jets and to explain them, magnetic fields of accretion disks should be involved. In co-operation with SAI MSU


– A catalog of 450 nearby galaxies with distances within 10 Mpc measured with the Hubble Space Telescope and BTA has been created. In spite of the lack of rich clusters around us and the presence of large volumes completely free from galaxies (voids), the mean luminosity densities and the mean density of hydrogen mass in the Local Universe is one and a half - twice as high as their mean global values. However, the mean local density of the baryon mass is only 2% of the critical density of the Universe, which is twice as less as the baryon density from the nucleosynthesis data (local paradox of the baryon mass). In co-operation with AO KNU (Kiev, Ukraine) and MPIfR (Bonn, Germany)
– A stage of multifrequency investigations of the near-zenith region at RATAN-600 with the world`s best sensitivity in the cm range has been completed. It is shown for the first time that the surface density of objects in the cm range exceeded their density in the dm range. The overwhelming majority of objects have been investigated in the cm range for the first time, and a few hundred objects are new objects of the radio sky.
– As a result of the earliest optical observations of the afterglow of the GRB 030329 at BTA, wide spectral features that point to relationship between a gamma-burst and a supernova explosion are discovered. In co-operation with ASC LPI RAS, SAI MSU, Institute of Astrophysics (Spain), MAO UNAS (Ukraine)

Hardware and methodological developments

– As a result of development of image slicers, polarization analyzers and reduction technique, the limiting magnitude of spectral observations at BTA with high spectral resolution (up to R=80000) has been increased by 3 times, the limiting magnitude of spectropolarimetric observations increased from 3 to 8 times (in the red and UV ranges, respectively).
– A wide-angle system (18x20 degrees) of high time resolution (up to 0.13 s) for real time detection of variable astronomical objects - optical transients of gamma-bursts, flare stars and novae, supernovae at early stages of their birth, and also near-earths moving bodies of natural and artificial origin -is created. In co-operation with Kosmoten and SRI RAS.