A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses:
  The Redshift Catalog
  We present the spectroscopic redshift catalog from a wide-field survey of the
fields of 28 galaxy-mass strong gravitational lenses. We discuss the
acquisition and reduction of the survey data, collected over 40 nights of 6.5m
MMT and Magellan time, employing four different multi-object spectrographs. We
determine that no biases are introduced by combining datasets obtained with
different instrument/spectrograph combinations. Special care is taken to
determine redshift uncertainties using repeat observations. The redshift
catalog consists of 9768 new and unique galaxy redshifts. 82.4% of the catalog
redshifts are between z=0.1 and z=0.7, and the catalog median redshift is
z=0.36. The data from this survey will be used to study the lens environments
and line-of-sight structures to gain a better understanding of the effects of
large scale structure on lens statistics and lens-derived parameters.
