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.
all-sky set of (B)-V-R photometric calibrators for Schmidt surveys.
GSPC2.1: First release