VLBI Observations

The VLA often participates in VLBI observations with the VLBA, and in Global Network sessions which occur three or four times per year. The VLA supports VLBI observations in either single-antenna or phased-array modes. Data are recorded on a Mark 5A disk recording system after the single-antenna or phased-array data have been passed through the VLA's VLBA data acquisition system. At this writing, we are just completing the implementation of phasing of the EVLA antennas together with the VLA antennas, so that the phased-array VLA will contain $\sim 25$ antennas added in phase rather than a maximum of $\sim 20$. A comprehensive document entitled `VLBI at the VLA' is available on the Web - point your browser to http://www.vla.nrao.edu/astro/ and look under `Proposer Information and Documentation'. Be aware that this guide is somewhat out of date, and will soon be revised.

VLBI at the VLA is overseen by Amy Mioduszewski and Mark Claussen. Either can be consulted for general information regarding matters such as phased-array or single-dish observations, or calibration of the VLA for VLBI. However, most VLBI projects involving the VLA, whether run during or outside of a Network session, will be assigned an AOC contact by the Scheduler. Queries from an observer concering specific information about a specific project should be directed to the AOC contact assigned to the project. If the project's principal investigator or a co-investigator is an AOC employee, then that person will be assumed to be the AOC contact.

See Section 4.15 for information on absentee observing.