The USNOB Archive is an implementation of the USNO-B1.0 Catalogue
that presents positions, proper motions, magnitudes in various optical
passbands, and star/galaxy estimators for 1,045,913,669 objects derived
from 3,648,832,040 separate observations. The data were taken from scans
of 7,435 Schmidt plates taken from various sky surveys during the last
50 years.
The catalogue is expected to be complete down to V=21; the estimated
accuracies are 0.2arcsec for the positions at J2000, 0.3mag in up to 5
colors, and 85% accuracy for distinguishing stars from non-stellar
objects.