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The Very Large Array (VLA) is operated by the National Radio Astronomy
Observary (NRAO), and located in Socorro, New Mexico. The array was officially
completed in October 1980, but observations started in 1976 -- although with
only a few antennas. The VLA archiving program will preserve all data taken
after mid-1976.
This radio telescope has three arms with 9 movable antenna's on each of the
three arms. Each antenna has a crossection of 25 m. The telescope is operated
in four configurations with various lengths of the antenna arms. The maximum
antenna seperations for the four VLA configurations are: A-36 km, B-11 km, C-3
km, D-1 km. Hybrid configurations with a long north arm are used to produce a
round beam for southern sources (south of -15 degree decination).
For the following frequencies full capabilities exist 90, 20, 6, 3.6, 2, 1.3
cm, and the VLA has partial capability at 400 cm. Observers should note that
in the years of sunspot maximum, daytime observations at 327 MHz are unlikely
to be successful in the smaller configurations because of solar interference,
and in the larger configurations because of a disturbed ionosphere.
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