(NRAO), federal observatory for radio astronomy, founded in 1956 and operated under contract with the National Science Foundation by Associated Universities, Inc., a group of major universities. The headquarters are at Charlottesville, Va.; the original observatory site is in Greenbank, W.Va., where the antennas, or radio telescopes, include a fully steerable 140-ft (43-m) paraboloid; an interferometer consisting of three steerable 85-ft (26-m) paraboloids; a horn-shaped antenna 120 ft (37 m) in length that is fixed in place; and two smaller, steerable paraboloids; a modern 328-ft (100-m) fully steerable telescope is under construction. At Kitt Peak, near Tucson, Ariz., NRAO has a 36-ft (11-m) steerable paraboloid; near Socorro, New Mexico, the NRAO's Very Large Array (VLA) consists of 27 parabolic dishes, each 82 ft (25 m) in diameter, mounted on a Y-shaped track with arms up to 14 mi (21 km) long. Finally, the observatory operates the Very Baseline Array (VLBA) consisting of ten radio telescopes placed around the earth that operate in unison. Principal research programs of the NRAO include the study of galactic structure, extragalactic radio sources, molecules in space, pulsars, quasars, and the evolution of stars and galaxies. Astronomers using the VLA have discovered filaments, jets, and high-temperature features in the center of our own galaxy and in extragalactic radio sources that may help explain the high energy of quasars. The system allows the study of the nuclei of active galaxies and helps determine distances to radio sources more accurately.

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