2 Observations

We have observed the entire IDS except for the planetary nebula NGC 6543, the bright galaxy NGC 6552 ( 18001+6636), which has a good IRAS measurement of the $12\,\mu$m flux, and the last three sources in the IDS list ( 18111+6636, 18115+6706, and 18116+6536) because of lack of observing time. On the whole, we got data for 94 IDS fields. In addition, we have observed the $25\,\mu$m detection (object 2-16 in Table 5 of HH87) with very unusual far-IR colours which turned out (Ashby & Hacking, private communication) to be a very high luminosity, distant post-starburst galaxy.

Observations were performed on 19 and 20 December 1996 and on 13 February 1997 via the CAM03 (beam-switching) AOT (Astronomical Observation Template: the instrument observing mode) with the LW3 filter, a pixel field of view of 6'' (since the detector comprises an array of $32\times 32$ pixels, its field of view is then of $3.2'\times 3.2'$), and a throw of 3' at constant declination. The typical number of exposures to stabilize the detectors to the sky background before each observation was ${N}_{\rm stab}= 60$ and the number of exposures used to measure the source flux was typically ${N}_{\rm exp} = 22$. An equal number of exposures was taken on sources and on reference fields (one per source); because of the detector stabilization problem, exposures on the reference field were taken after those on the source were completed (rather than taking on/off source exposures in sequence). The integration time per exposure was of 2.1 seconds. The exposures were more numerous for fields observed at the beginning of each set of concatenated observations, to allow sufficient time for instruments to stabilize in the new configuration. Observations were completed in a single cycle of source-reference field pointings.

Table 1 gives the observing log. Columns 1 and 2 list the source names according to Table 5 of HH87 and to the IRAS Faint Source Survey (FSS; Moshir et al. 1992). Columns 3 and 4 give the equatorial coordinates, for the equinox 2000, of the centers of the observed $3.2'\times 3.2'$ fields; these correspond to the coordinates listed by Ashby et al. (1996), which coincide with the coordinates of IRAS sources given by HH87 except for the 9 sources (3-02, 3-04, 3-08, 3-22, 3-35, 3-43, 3-74, 3-82, 3-89) for which the coordinates of optical identifications are provided. Column 5 gives the total time spent on each target, Col. 6 the observation dates, and Col. 7 the so called "TDTOSN'' numbers identifying each observation in the ISO data archive.