Guide Star Photometric Catalog

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Last Updated Jan 2001

Copyright 2001 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved.

The primary effort of the Catalogs and Surveys Branch of the Space Telescope Science Institute has been the construction of the Guide Star Catalog, both GSC-I and GSC-II. To support photometric calibration of these catalogs, CASB produced the Guide Star Photometric Catalog (GSPC-I) and now in collabortation with Osservatorio Astronomico di Torino are producing its extension GSPC II.

GSPC I is an all-sky set of photoelectrically determined BV sequences in the magnitude range from 9 to 15, generally near the centers of the fields of the GSC-I plates.

GSPC II is generally an extension of GSPC I sequences to V=19 in (B), V and R passbands based on CCD photometry. Its purpose is the calibration of the GSC-II. New northern sequences are being added to support the POSS-II currently in production and the first release (624 sequences) is now available to the public through data access. These sequences represent about one third of the total number of GSPC-II target fields. Our present efforts are focusing on quality control of the remainder of the in-house data, and on (re-)observations of the missing sequences, with the primary goal of publishing photometric calibrators for the entire sky in (B), V, and R passbands.