In December, 1995 the Hubble Space Telescope pointed at an undistinguished high-galactic latitude patch of sky in the northern hemisphere, and observed for 10 straight days. The result was the deepest optical image of the sky yet obtained: The Hubble Deep Field (HDF) (henceforth referred to as the Hubble Deep Field North, or HDF-N). The images allow detection of sources as faint as V = 30 in four bandpasses spanning the near-UV to the near-IR (Williams et al. 1996). The data were released to the community within one month of the observations and have been used in a wide variety of projects and publications, ranging from studies of the star-formation rate as a function of redshift, to studies of faint M dwarfs in the Galactic halo.
A second Southern Hubble Deep Field campaign was carried out between late September and October of 1998. The raw, pipeline calibrated and reprocessed data were released to the community on November 23, 1998. The rationale for undertaking a second deep field campaign followed from the wealth of information that has come out of HDF-N, and from the desire to provide a point of focus for similar studies of the distant universe from southern-hemisphere facilities. The observations of the Hubble Deep Field South (HDF-S) were similar in spirit to the original HDF. As was the case for HDF-N, approximately 150 consecutive orbits were devoted to a single telescope pointing. Additional flanking field observations were made surrounding the deep STIS, WFPC2 and NICMOS fields. I am a member of the HDF-S working group. I built and maintain the HDF-S web site at STScI, and I am a member of the NICMOS team.
The Hubble Deep Field South (HDF-S) campaign differs from the HDF-N campaign in several important areas: