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Hubble Space Telescope
HST/ACS Ultra Deep Field


03/16/2004 - The ACS-WFC raw data and the associated calibration files for the Hubble Ultra Deep Field are now available. Users are asked to retrieve them via anonymous ftp from caches at STScI rather than submit requests through the HST archive. Users may also request the raw data on DVDs by sending email to

Also, a nice Javascript viewer for browsing the UDF field is now available.

03/09/2004 - High-Level Science Products (reduced images, object catalogs and related files) are now available.

12/30/2003 - Images of the UDF, based on the GOODS V1.0 data release, are now available. These images are on the same astrometric grid as the final UDF dataset.

10/31/2003 - UDF Coordinate list released. A list of the 100 reddest objects in the UDF field is now available.


The ACS Ultra Deep Field (UDF) is a survey carried out using the Advanced Camera for Surveys (ACS) on HST and taking advantage of the Director's Discretionary time. The data will be made public. The UDF will consist of a single ultra-deep field (412 orbits in total) within the CDF-S GOODS area. Scientific drivers of the UDF include probing the tail of the reionization epoch, constraining the star formation history of the Universe, probing the faint end of the galaxy luminosity function, and tracking the origin, structure, and merger history of galaxies as they evolve onto and off the Hubble sequence.

The basic structure of the UDF Survey represents the consensus recommendation of a Scientific Advisory Committee to STScI Director Steven Beckwith, and supported by planning documents presented by a local Working Group, which has looked in detail at the implementation of the survey. Details of the final UDF adopted ACS parameters and the current status can be found below: