AAS Meeting #193 - Austin, Texas, January 1999
Session 13. Data Discovery Tools and Services
Display, Wednesday, January 6, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[13.01] The Status of the Digital Palomar Observatory Sky Survey (DPOSS)

S. G. Djorgovski, R.R. Gal, S. C. Odewahn, R. J. Brunner (Caltech), R. R. de Carvalho (ON/CNPq, Brasil)

The DPOSS is a digital version of the POSS-II photographic sky atlas. It covers the entire sky north of \delta = -3\circ in 3 bands, photographic JFN calibrated to the Gunn gri system, reaching to equivalent limiting magnitude of Blim ~22m. Fields are 6.5\circ square, spaced by 5\circ, so that ~40% of the sky is covered at least twice in each band. The plate taking is now essentially complete in J and F, and ~80% complete in N. The plates are digitised at STScI, with 1.0 arcsec pixels, resulting in ~3 TB of pixel data. These scans are processed independently at STScI (for the HST GSC-II catalog) and at Caltech and associated sites. A very extensive CCD calibration program is under way at Palomar and elsewhere, with a median of 2 CCD fields per plate. A great care is taken to assure the photometric uniformity to better than 0.1 mag, both across the plates and between the plates. The star-galaxy separation is expected to be accurate 90% or better down to ~1m above the plate detection limit. All of this represents a considerable technical advance in the analysis and calibration of large, photographically based digital sky surveys, resulting in a database which should support a very broad range of astronomical studies.

The end product of the survey will be the Palomar-Norris Sky Catalog, anticipated to contain > 50 million galaxies and > 2 billion stars, down to the survey classification limit, ~1m above the flux detection limit. Numerous scientific projects utilising these data have been started, and we will describe briefly some of them; they illustrate the scientific potential of the data, and serve as the scientific verification tests of the survey.

The data release to the general community is expected to start in the early/mid 1999. This work is supported in part by a grant from the Norris Foundation.

The author(s) of this abstract have provided an email address for comments about the abstract: george@oracle.caltech.edu

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