Arecibo radio telescope
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Arecibo radio telescope(a-rĕ-see -boh) A radio telescope, 305 meters in diameter and spherical in shape, sited in a natural hollow near the town and seaport of Arecibo, Puerto Rico. It is the world's largest single-dish telescope. It is operated by the National Astronomy and Ionosphere Center of Cornell University and has been in use since 1963. The original lining was replaced in the early 1970s by nearly 40 000 perforated aluminum panels in order to improve performance at shorter wavelengths, including the 21-cm line of hydrogen. It now observes at frequencies between 50 MHz and 10 GHz, using a small subreflector system (the ‘mini-Gregorian’) for work between 1–10 GHz. Although not steerable, the antenna can observe in any direction up to 20° from the zenith by moving the feed antennas along the north–south girder on which they are carried, 130 m above the dish. The Arecibo dish, with its huge collecting area, can also be used for radar astronomy and atmospheric science.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006