The CNOC cluster redshift survey catalogs .1. Observational strategy and data reduction techniques

We describe in detail the observational and data reduction techniques of a large redshift survey using multiobject spectroscopy designed to obtain similar to 2600 faint galaxy redshifts in fields of 16 rich clusters of galaxies with redshifts between 0.2 and 0.55. The primary goal of the survey is to establish whether the mass-to-light ratio of clusters rises with distance from the cluster center. To maximize multiplexing capability, we use similar to 1500 Angstrom wide band-limiting filters matched to the major features of spectra of galaxies at the cluster redshifts to allow for multitiering of spectra. Typically 80-110 spectra can be observed using a single slit mask. The area covered for each cluster ranges from about 1.5 h(100)(-1) Mpc squared to 1.5 h(100)(-1) Mpc X 6 h(100)(-1) Mpc. We describe the observing procedure, which involves real-time photometry and computer-based mask design and mask fabrication on site, allowing for the efficient use of telescope time. The spectroscopic data are extracted semiautomatically, and redshift measurement is performed using cross-correlation techniques. A detailed discussion of the determination of the completeness of the final redshift sample as functions of magnitude, color, geometric position, and redshift is also presented.