CAOBS Features

CAOBS records the attenuator settings and sampler levels at the end of each scan. This allows the automatic attenuator setting feature to know how to set the settings if sources in your schedule file have different requirements (using envflg). The automatic setting feature (servoing) does not operate on antennas that are disabled or while antennas are driving. Refer to the envflg option to find out how to use this feature to record attenuator settings for sources that vary greatly in amplitude.

At the start of every scan, CAOBS writes a scan header to the data file. This header consists of the source name, the RA, Dec, frequency and $uvw$. The fundamental equinox for all CAOBS calculations is J2000 and it is recommended that coordinates be expressed in this system. You can however use B1950 in CAOBS and SCHED. Coordinates expressed in B1950 are precessed to J2000 before the scan starts and subsequent calculations are done in the J2000 system.