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Up: The Effelsberg 21 cm

3. Reduction

The principles of the applied data reduction have been already described in Paper I. However, for maps observed in orthogonal directions we applied the program PLAIT (Emerson & Gräve 1988), which is quite effective in reducing scanning effects. The large scale structures have been added (see Paper I for details) by using the data from the 1420 MHz Stockert continuum survey (Reich 1982; Reich & Reich 1986). This survey is limited to the declination range above tex2html_wrap_inline1244 and was used therefore to correct the data for Galactic longitudes tex2html_wrap_inline1246 233tex2html_wrap1170. For longitudes tex2html_wrap_inline1250 233tex2html_wrap1170 corrections have been applied by scaling the 408 MHz all-sky survey (Haslam et al. 1982) with a temperature spectral index of tex2html_wrap_inline1254 tex2html_wrap_inline1256. A deviation in the spectral index of tex2html_wrap_inline1258 results in a temperature change of the maximum of the background emission of about 0.4 K.

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