The Special Astrophysical Observatory Russia's main center for ground-based space research. Operated by the Russian Academy of Sciences, it is located at an altitude of 2,100 m on Mount Pastukhov in the Caucasus mountains of Karachaevo-Cherkesia, in the south of the country. Its main instruments are the 6-meter Bolshoi Azimuthal Telescope and the 600-meter RATAN-600 radio telescope.