track source
Start tracking a new source.
Source source
track 3c273
track zenith
If while tracking a source, the source falls below the minimum elevation reachable by the CBI, the control system will continue to track the source in azimuth and parallactic angle, but the elevation will be held at its lower limit until the source rises above it.
The orientation of the field of view seen by the CBI is automatically kept from rotating during tracking by rotating the deck drive to track the changing parallactic angle of the source.