  RVSAO is a set of programs to obtain redshifts and radial velocities from
digital spectra. RVSAO operates in the IRAF(Tody 1986, 1993) environment. The
heart of the system is xcsao, which implements the cross-correlation method,
and is a direct descendant of the system built by Tonry and Davis (1979). emsao
uses intelligent heuristics to search for emission lines in spectra, then fits
them to obtain a redshift. sumspec shifts and sums spectra to build templates
for cross-correlation. linespec builds synthetic spectra given a list of
spectral lines. bcvcorr corrects velocities for the motion of the earth. We
discuss in detail the parameters necessary to run xcsao and emsao properly.
  We discuss the reliability and error associated with xcsao derived redshifts.
We develop an internal error estimator, and we show how large, stable surveys
can be used to develop more accurate error estimators.
  We develop a new methodology for building spectral templates for galaxy
redshifts. We show how to obtain correlation velocities using emission line
templates. Emission line correlations are substantially more efficient than the
previous standard technique, automated emission line fitting.
  We compare the use of RVSAO with new methods, which use Singular Value
Decomposition and $\chi^2$ fitting techniques.
