These configurations are denoted D , C , B , and A respectively. These hybrid configurations are especially well suited for observations of sources south of or north of . The array completes one cycle through all four configurations in approximately a 16 month period. The configuration schedule for 2000 through 2002, and the approximate long-term schedule to 2003, are outlined in Tables 1 and 2 . Refer to Section 4.1 for information on proposal deadlines, and on how to submit an observing proposal.
Most observing runs have durations of a few hours, with only one, or perhaps a few, target sources.
However, since the VLA is a two-dimensional array, images can be made with data durations of less than one minute. This mode, commonly called snapshot mode, is well suited to surveys of relatively strong, isolated objects. See Section 3.16 for details. The VLA can be broken into as many as five sub-arrays, each of which can observe a different object at a different band. This is especially useful for multi-band flux density monitoring observations, and for observing compact objects for which the VLA's full imaging capability and sensitivity are not required.