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2. Observations

The observations were taken with the Australia Telescope Compact Array in 1994 January and September in 6A-configuration. The resolution is 6tex2html_wrap1182 in right ascension and tex2html_wrap_inline1152 10tex2html_wrap1182 in declination. The full width at half maximum (FWHM) of the primary beam (PB) of the antennae at the frequency of the observations is tex2html_wrap_inline1156. The area of the Disk region was covered with 910 pointing centres, separated by 30tex2html_wrap1138. The coverage is complete for offset tex2html_wrap_inline1160 which translates to a primary-beam response (PBR) of 0.25. For observational convenience, the observations were taken in two "g blocks''; one for tex2html_wrap_inline1162 (part B) and one for tex2html_wrap_inline1164 (part A) as can be seen in Fig. 1. In part A the pointing centres are not distributed in the honeycomb pattern described in Paper I, but rather in a rectangular pattern, for reasons of temporary observational incompetence. The data were taken in two linear polarizations, using a total bandwidth of 4 MHz and 1024 spectral channels (channel separation 3.9 kHz, correlator frequency resolution 4.69 kHz). The spectral band was centred at 1612 MHz, offset by 0.231 MHz from the rest frequency of the OH transition. No Doppler tracking was used during the observations. The velocity coverage is (tex2html_wrap_inline1166) for all fields except those with tex2html_wrap_inline1168 in part A, for which the coverage is (tex2html_wrap_inline1170) because they were partly observed in September. The data were Hanning smoothed to give a velocity resolution of tex2html_wrap_inline1172 (7.8 kHz). The observations were taken using a "gmosaic" mode, to optimize uv-sampling (for details see Paper I). The secondary calibrators observed in the Disk region were 1740-517 (part B) and 1414-590 (part A). The primary calibrators are the same as in the Bulge region, 1934-638 and/or 0823-500. The average integration time per pointing is 9 min, resulting in an average noise level in empty cubes of 29.6 mJy.


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