Users allocated VLBA observing time will be sent detailed observing schedule preparation instructions. Currently, the preparation of schedule files for observations in VLBA and Mark III formats is best handled by running software on AOC computers, with local assistance provided by the VLA/VLBA data analysts and AOC scientific staff. This arrangement ensures that observing schedule files (1) contain proper antenna electronics setup information, (2) are fully compatible with antenna hardware and control software, and (3) make use of the latest schedule preparation software.
Projects in a VLBA format are scheduled using the NRAO program SCHED, which is which is available for use both at the AOC and elsewhere (Walker 1997). (Projects requesting a Mark IV format on the VLBA will be observed in a VLBA format.) Most projects in a Mark III format are scheduled with the Haytack program PC-SCHED; Section 26.1 gives contact information. The so-called DRUDG file output by PC-SCHED is translated at the AOC for use by program SCHED, which is then used to create the observing schedule files for the VLBA.