Gaia EDR3 2874131783079014016 , the SIMBAD biblio

Precise and accurate CCD-based UBVRI photometry is presented for ∼2000 stars distributed around the sky in a declination zone centered approximately at +50deg. Their photometry has been calibrated to the standard Johnson UBV and Kron-Cousins RI systems through observations of the UBVRI standard stars presented in the various works of Landolt. The magnitude and color range for these stars are 12 <= V <= 22 and -0.3 <= (B - V) <= 1.8, respectively. Each star averages 13 measures in each UBVRI filter from data taken on 41 different photometric nights obtained over a 21 month period. Hence, there now exists a network of faint UBVRI photometric standard stars centered on the declination zones δ=-50deg, 0deg, and +50deg.