UCM Survey

The 80/120 cm f/3 Schmidt Telescope of the Calar Alto German-Spanish Observatory (Almería, Spain), equipped with a 4 deg full aperture objective prism, was used in this survey.

The IIIaF emulsion and a RG630 filter results in a useful spectral range from 6400 to 6850 Å (dispersion of 1950 Å/mm at Hα), i.e. Hα line in emission can be record for objects up to z<0.04.

Field coverage is 5.5x5.5 square degrees in plates 24 cm wide (plate scale is 86 arcsec/mm).

The IIIaF plates were hypersensitized by baking them in an atmosphere of N₂ gas at 65 C for 6 hours prior to exposure.

Without widening, the spectra were kept to a width of 0.06 mm. Dispersion runs along the north-south axis. A well-exposed spectrum is about 0.4 mm long.

Quality standards

1. good seeing (no worse than 3 arcsec) and excellent guiding,
2. no cloud interference
3. no exposure interruption
4. telescope near the meridian, i.e. hour angle between 21h30m and 2h30m.