An observatory of the Russian Academy of Sciences, at an altitude of 2070 m on Mount Pastukhova in the Caucasus Mountains of southern Russia. It is the site of the 6-m Large Altazimuth Telescope (in Russian, Bol’shoi Teleskop Azimutal'nyi, or BTA), opened in 1975; the mirror was replaced in 1979. Also at the Observatory are a 1-m reflector, opened in 1990, and a 0.6-m reflector, opened 1994. About 20 km to the northeast, at an altitude of 970 m, is the RATAN-600 radio telescope.

http://www.sao.ru/Doc-en/ Official observatory website.