A radio telescope at the Special Astrophysical Observatory near Zelenchukskaya in southern Russia, which began operation in 1975. Its name is an abbreviation of Radio Astronomy Telescope of Academy Nauk (Sciences). It consists of 895 tiltable panels arranged in a ring 576 m wide, which can be used as a unit or as four individual sections, and observes at wavelengths of 1 to 50 cm.
http://www.sao.ru/ratan/ Official telescope website.