Arecibo Observatory

Arecibo Observatory radio-astronomy facility located at Arecibo, Puerto Rico, that includes the world's largest single-dish radio telescope. It was completed in 1963 and is operated by Cornell Univ. under contract with the U.S. National Science Foundation. The principal instrument is a fixed antenna of spherical section, 1,000 ft (305 m) in diameter, that is built into a natural limestone bowl. Although the antenna is too large and heavy to be moved, it can be pointed as much as 20° from the zenith by moving the line feeds to the antenna's focus. As a result of the resurfacing of the antenna, which was completed in 1974, observations are possible up to a frequency of 4,000 MHz. A 100-ft (30-m) satellite antenna can be used in conjunction with the large antenna for interferometer observations. In addition there is a wide range of instrumentation for measuring ionospheric conditions. Principal research programs include studies of radio emissions from many types of objects, especially the cores of supernovas called pulsars; radar studies of comets and asteroids; and ionospheric studies.

Arecibo Observatory The site of the world's largest radio astronomy dish, 305 m in diameter, opened in 1963 and upgraded in 1974 when the original wire-mesh surface was replaced by solid panels. The observatory is situated 12 km south of Arecibo, Puerto Rico, and is operated by the National Astronomy and Ionosphere Center (NAIC), which has its headquarters at Cornell University, New York State. The dish is suspended in a natural hollow in the ground, and scans a strip of sky overhead as the Earth rotates. Radio sources can be tracked within 20° of the zenith by using movable feeds suspended above the stationary reflector, giving coverage in declination from about 38° north to 1° south. The Arecibo dish is used for atmospheric studies as well as astronomy. http://www.naic.edu/