Optical spectra and redshifts for seventy-one galaxies

Spectra of 71 galaxies have been obtained with an image tube spectrograph on the 1.9-m telescope of the South African Astronomical Observatory at a reciprocal dispersion of 215 A mm-1. The spectra have been traced with a microdensitometer to identify features, and have been measured for redshift with a travelling microscope. Complete lists of absorption features and emission lines seen in the spectra have been compiled. The rest wavelengths of the absorption features have been revised and have been used to derive redshifts with external mean errors of the order of +- 60 km s-1. There is, however, marginal evidence of a scale error in our data. Sandage's findings of systematic differences between H I radio and optical redshifts is confirmed. The differences, however, are not simple zero point or scale errors, and zero point corrections are insufficient to bring the optical and radio data into systematic agreement. The redshifts include values for galaxies in 18 rich clusters in the Indus Supercluster area, and our data also include values tending to confirm suggestions of cell structure of the Coma Supercluster. (author)