Sky & Telescope April 1979 [antikvár]

This architect's drawing shows the completed RATAN-600 radio telescope. Inside the ring, 576 meters in diameter, is a flat reflector 400 meters long and five secondary feeds which operate along railroad tracks, being moved from one to another bythe turntable at the center of the radial array.The Soviet RATAN-600 Radio TelescopeD. V. Korolkov and Yu. N. Pariiskii, Leningrad Branch,Special Astrophysical Observatory, U.S.S.R. Academy of Sciences, PulkovoNear Zelenchukskaya in the northern Caucasus, a giant radio telescope has recently become almost fully operational. Located 20 km northeast of the 6-meter optical reflector (described in Sky and Telescope for November, 1977, page 356), it too is part of the Special Astro-physical Observatory of the U.S.S.R. Academy of Sciences. The name of thisnew instrument, RATAN-600, is an acronym for jRadio Astronomy Telescope of the Academy of Sciences (iVauk) and the approximate diameter in meters of the ring-shaped primary reflector.Each of the 895 panels that make up the ring, 576 meters across, is 2 by 7.4 meters in size. These provide a total collecting area of about 13,000 squareThe Special Astrophysical Observatory is located in the northwest Caucasus, just above the village of Zelenchukskaya. Here are the RATAN-600 (double circle) and the 6-meter reflector (star), 1,100 meters higher, where the Nizhnii Arkhyz scientific compound has been developed. Open circles indicate other observatory sites in the southwestern part of the Soviet Union.meters, roughly V^ that of the 1,000-foot dish at Arecibo, Puerto Rico. Since the RATAN-600 is designed to work in the short-wavelength portion of the radio spectrum, between 8 mm and 20 cm, each panel must be positioned accurately. Thus, they are provided with a one-meter range of radial displacement as well as the ability to tilt vertically and horizontally.Inside the ring is a tillable flat reflector, 400 meters long in the east-west direction and 8.3 meters high. There are also five feed systems (three being operational at present), each equipped with an 8-by-5.5-meter secondary reflector, horn-type antenna, and cabin for receiving equipment. As shown in the artist's drawing above, these secondary units operate along radial railroad tracks north of the flat reflector and along two arcs south of it. A special feed now under construction will utilize the entire ring for observations near the zenith; in this mode of operation the flat reflector will be lowered down to the ground.By using cylindrical paraboloidal reflectors the secondary feeds transform the cylindrical radio waves from the primary ring into spherical waves. Since the shape of the primary reflector and the positions of the secondary feeds can be changed according to the altitude of the source beingSky and Telescope April, 1979