Description :

The Guide Star Photometric Catalog II (GSPC-II) is an all-sky catalog of secondary "standard-stars" that were used to perform the photometric calibration of the GSC-II. The GSPC-II typically consists of stars between 14-19th magnitude near the center of each of the Palomar and UKSTU survey fields. These were all observed using CCD detectors from a number of different observatories.

References :

An all-sky set of (B)-V-R photometric calibrators for Schmidt surveys. GSPC2.1: First release
Bucciarelli et al 2001 A&A 368, 335

Properties :

Data Access :
GSPC 2.1 : download (from STScI)
GSPC 2.4 : download (from STScI) | download (from CDS)