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VLAAbbrev. for Very Large Array. An aperture synthesis radio telescope near Socorro, New Mexico, and part of the National Radio Astronomy Observatory. The VLA is the most effective instrument in the world for general-purpose radio-astronomical imaging. Its antennas are placed on a Y-shaped track that allows for high-resolution observations of sources over a wide range of declinations. The three arms of the configuration are 21, 18.9, and 21 km long, and together hold 27 dish antennas that can be positioned at 72 different observing locations. Each dish is 25 meters across, with a surface accuracy of 0.5 mm, and weighs 193 tonnes. The dishes can be arranged in one of four principal configurations, from ‘A’ (with a maximum baseline of 36.4 km) to ‘D’, which is the most compact and has a minimum baseline of 33 meters. Their scales vary by the ratios 1:3.2:10:32. The VLA generates 351 simultaneous baselines and can therefore synthesize maps relatively quickly. It has receivers for observing in six wavelength bands centered near 90, 20, 6, 3.6, 2, and 1.3 cm.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.