PreCam, a Precursor Observational Campaign for Calibration of the Dark
  Energy Survey
  PreCam, a precursor observational campaign supporting the Dark Energy Survey
(DES), is designed to produce a photometric and astrometric catalog of nearly a
hundred thousand standard stars within the DES footprint, while the PreCam
instrument also serves as a prototype testbed for the Dark Energy Camera
(DECam)'s hardware and software. This catalog represents a potential 100-fold
increase in Southern Hemisphere photometric standard stars, and therefore will
be an important component in the calibration of the Dark Energy Survey. We
provide details on the PreCam instrument's design, construction and testing, as
well as results from a subset of the 51 nights of PreCam survey observations on
the University of Michigan Department of Astronomy's Curtis-Schmidt telescope
at Cerro Tololo Inter-American Observatory. We briefly describe the preliminary
data processing pipeline that has been developed for PreCam data and the
preliminary results of the instrument performance, as well as astrometry and
photometry of a sample of stars previously included in other southern sky
surveys.
