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Session 64 - New Digital Surveys in the Optical and Near IR: Technical Challenges and Scientific Opportunities - II.
Topical, Oral session, Wednesday, June 10
Friars,
The new modern sky surveys from the Palomar Oschin Schmidt and the UK Schmidt are nearly complete. The predominant community applications of these surveys, for both research directly dependent on the images and that using catalogues produced from them, is based on digitizations of the photographic material. The ST ScI Second Digitized Sky Survey (DSS-II) samples these plates at 1" interval, resulting in 4 Tbyte collection of 1.1 Gbyte plate-images. Raw images are archived on opical media at ST ScI, are distributed to a small number of international sites that provide community access, and are used to produce the second Guide Star Catalog (GSC-II). In order to preserve generality in the exploitation of these data, we maintain the connection between the images (plate scans) and the GSC-II catalog objects by associating the plate-calibration data (astrometry, photometry, classification) in FITS-like header structures pertinent to each plate.
GSC-II plate processing, with a goal of producing positions, proper motions, magnitudes, and colors to the plate limit, is organized in the COMPASS database. COMPASS, an object-oriented system with an estimated size at completion of 4 Tbytes, is structured for optimizing calibrations and is organized on the sky with the hierarchical triangulated mesh developed by the SDSS Archive team. COMPASS is also used to support consistent object naming between plates, as well as cross-matching with other optical surveys and with data from other wavebands. A much smaller ``export" catalogue, in ESO SkyCat format, will also be produced.
