Single and Multi-dish mode

Observations in multi and single-dish modes are made using pointings cross-scans in beam-switching mode after a careful CALIBRATION at the source elevation. Calibrations on planets are made off source to avoid contamination by source emission (although even Saturn contributes to only 6 K to the total noise). Skydips at the beginning and/or end of observations can provide us a better estimate of the calibration accuracy. Several pointing scans may be done at various elevations. Before starting the observations, tests of the beam-switch and the value (or measure) of the Gains USB/LSB are automatically asked. The gain value is used with USB and LSB frequencies to calculate a weighted flux of the planets, including the gain USB/LSB. If it is impossible to measure the gain correctly (1 or 2 antennas only), be careful about the value you enter (ask the operator on duty).

The planets are selected in priority at the beginning of the observations, a flag counts the planets measurements and signals when no planet is available. Afterwards, only the brightest quasars are observed :

Table 1: Strong sources observed in single-dish mode (Apr-1992). cm

3C84
3C273
3C279	(1)
3C345
3C454.3
NRAO530	(2)
0420-014
0851+202	(2)
W3OH

cm (1) Not used, too close to 3C273.
(2) Sometimes used, but may be too weak.