Astron. Astrophys. 364, 349-368 (2000)

2. Observations

The data were obtained during the spring of 1998 using the prime-focus wide-field UH8K CCD Camera (Metzger et al., 1995) at the Canada-France-Hawaii 3.6 m Telescope. The camera is a mosaic of 8 2k4k CCD chips covering a total area of with a scale of /pixel. We observed four fields with R.A. offset of , and , hence overlapping by 5´, 5´ and 10´ (Table 1). The observations were done in bands V (Johnson) and I (Cousins). The total area of the survey is 0.68 deg². The limiting magnitudes are and (see Sect. 3.3 on the completeness). The central galactic coordinates are , . At such high galactic latitudes, the reddening is mag (Burstein & Heiles, 1982). This is an upper limit because we observed in V and I (reddening). We neglect both the absolute reddening and the relative reddening between the fields. Table 1 gives the characteristics of each field. The seeing is between and for both filters during the whole night. The exposure time is 1200 sec for all fields. Fig. 1 shows the map of the 19,500 galaxies detected to (limiting magnitude of the correlation analysis, cf Sect. 3.3). In spite of the bad cosmetics of CCD#4 (visible in the upper right corner of Fig. 1), the overlaps provide homogeneous sampling of the area, except for the regions containing bright stars (empty circle in the upper middle) and the gaps within the UH8K Mosaic CCD chips.

Fig. 1. Map of 19,506 galaxies to . Bad cosmetics, intervals between CCD chips, and saturation artifacts due to bright stars are masked (shown as empty areas).

Table 1. Field characteristics

© European Southern Observatory (ESO) 2000

Online publication: January 29, 2001
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