Calibration

Every scan was bracketed by boresight calibrations. We use a linear interpolation from these to obtain an amplitude and phase correction for each point on the scan.

The boresight observations therefore give us an indication of the data quality. Figures 1 and 2 show the calibration data for each map. Both are excellent.

The phase/time trends are dominated by the satellite motion, seen with an East-West interferometer of $\sim$ 200m baseline. (The satellite movement was $\sim$ 0.05 degrees in azimuth over the course of the observation).

Figure 1: Calibration data from the boresight calibrations of the May 29 run. The large excursions around 14:00 UT are due to a focus check

Figure 2: June 12 calibration. The large phase excursions near 28:00 UT are due to focus checks