The primary purpose is to determine the receiver's maximum gain focus position. The on-source position is at the specified coordinates. The extent of the map is determined by the step sizes and the number of Points in each direction. The fastest stepping is in R.A., longitude, or azimuth. A reference off position and frequency of occurrence may be specified.
Successive sweeps are in opposite directions.
Data are recorded continuously during the whole map, even while reversing sweep direction. The primary purpose is for polarization measurements. The direction of elevation motion is determined by start and stop elevations.