PEAK, if specified, will cause commands to be issued to tell some antennas to peak up their pointing. NOPEAK causes SCHED to stop issuing those commands.
As of March 1999, PEAK is no longer used to control VLA pointing. Please see parameter VLAPEAK.
For the VLBA, if PEAK is greater than 0, a peakup will be done using the channel number specified by the PEAK argument. The peakup begins either when the scan starts, or when the antenna reaches the source, whichever is later. But the on-line system will wait for a maximum of 30 or 40 seconds to reach source before giving up. If it will take longer than that to reach source, a dummy scan or a gap between scans should be inserted. The peakup routine reads the total power after being on each position for 2 seconds and then goes on to the next position. The pattern contains 10 points. Therefore the peakup will take 20 seconds plus slew times which may be as little as 30 seconds - call it 45 seconds to be conservative - at high frequencies. It could take significantly longer at low frequencies but there is no good reason to use reference pointing there. After the peakup is done, the results will be used until either another peakup is done or the project code changes. Hopefully, we'll have some way to turn it off eventually.
It will be common to peak up at a different frequency from that being used for observing (eg peak at 7mm for 3mm observations). It will also be common to peak on a line source during a continuum observation. Therefore a different setup file will be needed for the peaking scans. It is reasonable to use the standard pointing setup files. They have names like pt7mm.set. They use FORMAT=NONE which causes the on-line system on the VLBA to not touch the formatter. Note that this is very likely to mean that any pulse cal data gathered during such scans are likely to be spurious.
See the section on reference pointing for much more information on easy ways to insert pointing scans.
This command has no effect on the VEX file, there is currently no means to peak up telescopes that are controlled through the PCFS.
The following paragraph is obsolete as the 140' is no longer in use for VLBI. But SCHED can still make the cards, so the description is retained. For the Green Bank 140' (NRAO type files), ``cards'' will be issued that request that the antenna peak up on source. This will happen for any PEAK argument greater than or equal to zero. It can be turned off by setting a negative argument or by specifying NOPEAK. The peak takes about 5 minutes in addition to slew time on the 140'.