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2. Observations

The observations started in 1982 and were finished in March 1988. However, during the reduction stage numerous areas have been found to be distorted by low level interference or by far-sidelobe contributions, which may pick up solar radio emission even at very large angular distances from the observing direction (Kalberla et al. 1980). Therefore several small areas have been subsequently reobserved between December 1990 and February 1994.

We used the same receiver as described already in Paper I (see Table 1) for the observations done until March 1988. The two channel (left- and right-hand) FET based total power receiver (tex2html_wrap_inline1220 = 45 K) was installed in the prime focus of the telescope (Schmidt & Wongsowijoto 1983). For the majority of observations the centre frequency was set to 1408 MHz or 1410 MHz, but sometimes it was necessary to change to 1430 MHz or 1440 MHz because of the actual interference situation. For the same reason the standard bandwidth of 20 MHz was sometimes reduced to about 10 MHz bandwidth. Very few observations have been made with a bandwidth of 40 MHz.

A new sensitive L-band receiving system based on cooled HEMT amplifiers has replaced the FET receiver in 1990 and has been used for all reobservations of distorted areas. Its properties for continuum observations have been already described by Reich et al. (1992). The new receiver is quite similar to the previous receiver except that its system temperature is reduced to about 30 K.

The method of observation was basically the same as described in Paper I. The telescope has been moved between Galactic latitudes tex2html_wrap_inline1190 with a speed of 4tex2html_wrap1170/minute. However, as the strength and gradients of the diffuse Galactic emission are small in the anticentre direction if compared with the properties in the first Galactic quadrant, we have made also observations by moving the telescope in longitude direction for l tex2html_wrap_inline1228 162tex2html_wrap1170. The length of the longitude scans has been chosen in a way that they end in regions with weak emission. Extensions towards +5tex2html_wrap1170 latitude have also been observed in longitude at different scan length.

Calibration is based on 3C 286 assuming 14.4 Jy. Several secondary calibrators have been observed in addition (see Paper I). Almost all areas have been observed twice.


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