PTVLBA tells SCHED to write a VLBA pointing sequence in the VLBA control file for this scan. NOPTVLBA tells SCHED to stop writing such sequences. This parameter should only be of interest to VLBA operations staff. Note that this is not a peak in the sense that the antenna does not go to the derived position after the pattern. It is used for measuring pointing offets and pointing equations. Parameters PTSLEW and PTDUR set, respectively, the time allowed to get to source and the time spent at each position in the pointing pattern.