We describe methods for extracting quantitative spectra and astrometric positions from objective prism plates. In particular, we have studied 7161 stars in eight fields along the south Galactic meridian using the 6{deg}+4{deg} objective prisms on the Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory. In this paper we concentrate on techniques for deriving radial velocities and astrometric positions from opposed dispersion plate pairs. For our data the typical accuracy in radial velocity is ~8km/s. A catalog of 108 stars with high radial velocities is presented, which is complete (and unbiased in either kinematics or metallicity) to a limiting B magnitude of 12.5 in the eight fields studied. Only two of this sample of 108 stars have previously reported radial velocities.