The frequency coverage is 74 MHz to 50 GHz (400 cm to 0.7 cm). This allows for a short period of improved imaging of extremely northerly or southerly sources. Moves to smaller configurations are done in two stages, first shortening the east and west arms and later shortening the north arm. The observatory normally cycles through all the various possible configurations (including several hybrids) every 16 months the antennas are moved every three to four months. There are four commonly used configurations, designated A (the largest) through D (the tightest, when all the dishes are within 600 metres (2,000 ft) of the center point). The angular resolution that can be reached is between 0.2 and 0.04 arcseconds. Route 60 at a level crossing-and a specially designed lifting locomotive ("Hein's Trein"), the antennas can be physically relocated to a number of prepared positions, allowing aperture synthesis interferometry with up to 351 independent baselines: in essence, the array acts as a single antenna with a variable diameter. Using the rail tracks that follow each of these arms-and that, at one point, intersect with U.S. The antennas are distributed along the three arms of a track, shaped in a wye (or Y) -configuration, (each of which measures 21 kilometres (13 mi) long). The radio telescope comprises 27 independent antennas in use at a given time plus one spare, each of which has a dish diameter of 25 meters (82 feet) and weighs 209 metric tons (230 short tons). The NRAO is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. It is a component of the National Radio Astronomy Observatory (NRAO). The VLA stands at an elevation of 6,970 feet (2,120 m) above sea level. Astronomers using the VLA have made key observations of black holes and protoplanetary disks around young stars, discovered magnetic filaments and traced complex gas motions at the Milky Way's center, probed the Universe's cosmological parameters, and provided new knowledge about the physical mechanisms that produce radio emission. Each of the massive telescopes is mounted on double parallel railroad tracks, so the radius and density of the array can be transformed to adjust the balance between its angular resolution and its surface brightness sensitivity. The VLA comprises twenty-eight 25-meter radio telescopes (twenty-seven of which are operational while one is always rotating through maintenance) deployed in a Y-shaped array and all the equipment, instrumentation, and computing power to function as an interferometer. It lies in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, approximately 50 miles (80 km) west of Socorro. Jansky Very Large Array ( VLA) is a centimeter-wavelength radio astronomy observatory in the southwestern United States. One of the 28 radio telescopes undergoing maintenance in "The Barn"
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