Regardless of the recording format, VLA schedule files can be made using the NRAO SCHED program, which is available via anonymous FTP, as described in the section in ``The SCHED User Manual'' on installing SCHED. This manual is available from the VLBA astronomer's page. Ancillary files for SCHED, including sources, stations, locations, and frequency catalogs, plus setup files, are distributed with the program. Because SCHED and its ancillary files are continually evolving, it is best to make schedules using the latest versions. If you have trouble with SCHED contact Craig Walker (see Section 17).
Effective with the 2001 January 12 release of SCHED, the new international definition of the standard VLBI frequency for 43 GHz was adopted. That frequency is outside the VLA's old definition of band code ``VQ''. Therefore, until further notice, SCHED will always write complete local-oscillator and fine-tuning cards (see Section 16.2) for VLBI observations at 43 GHz so that there is no frequency ambiguity. This document assumes that the SCHED release of 2001 January 12 or later will be used for schedule file preparation.
Absentee observers can obtain assistance with VLA file preparation from the VLA/VLBA data analysts (see Section 17), who run, on AOC workstation aspen, a SCHED keyin file provided by the observer. The SCHED keyin file contains the SCHED commands desired by the observer. SCHED's many VLA-related parameters are described in its user manual. If the program's principal investigator is an AOC employee, then that person must make their own VLA schedule files and must coordinate file submission with the data analysts. The data analysts may be consulted for file preparation tips; this is especially useful if the NRAO OBSERVE or jobserve programs are involved.
The VLA has two VLBA tape drives, each of which accommodates 14 head
positions. Only ``thin'' (
m) tapes can be used. A thin tape
length is about 17600 feet. All thin tapes recorded at the VLA will
be written at high density. Since two VLBA tape drives are available,
tape changes can be instantaneous. However, be warned that if one
drive is inoperable, a normal tape change must be done on the other
drive; this will generally lead to data loss only at the beginning of
the new tape. Further tape details are given in
Section 14.
The information that absentee observers must provide to the data analysts is listed below. For a Network program, this information is due at least two weeks before the start of the appropriate Network session. For a non-Network program, this information is due by the schedule file due date assigned by Barry Clark (see Section 17). The required information should be transmitted electronically, either by e-mail to vlbiobs@nrao.edu or else by depositing files via FTP on AOC workstation aspen in subdirectory /home/aspen6/astronomy/mmmyy/bbbbb, where ``mmmyy'' is a code for the month and year (e.g., apr02) of program with code ``bbbbb'' (e.g., bq001).
Observers using VLBA formats must provide a SCHED keyin file. The desired VLBA setup file information must be included in the keyin file, via either setinit sections or setup file names. Mark 3 formats are rarely used these days; please consult your AOC contact for futher information and advice if you must use such a format.
Although most absentee observers will mainly interact with the data analysts, they can also reach the VLA operator and the VLBA array operator as indicated in Table 1. A few other useful phone numbers are +1-505-835-7405 for the VLBI area at the VLA, and +1-505-835-7252 or 7253 for the VLBA correlator operator at the AOC.
| VLA Operator | VLBA Array Operator | ||
| Switchboard | +1-505-835-7000 | +1-505-835-7000 | |
| Phone | +1-505-835-7180 or 7181 | +1-505-835-7250 or 7251 | |
| FAX | +1-505-835-7413 | +1-505-835-7027 | |
| observe@nrao.edu | vlbaops@nrao.edu | ||
| Paper mail | VLA Operations | VLBA Operations | |
| NRAO | NRAO | ||
| P.O. Box O | P.O.Box O | ||
| Socorro, NM 87801, USA | Socorro, NM 87801, USA |