Optical and near-infrared calibration of AGN field stars: An all-sky network of faint stars calibrated on the Landolt system

We present a total of 12,436 photometric measures of 371 field stars of 26 quasars in the visible (UBV RI) and 22,276 photometric measures of 122 fiel d stars of 13 quasars in the near-infrared (JHK), giving a total of 34,712 measures. Of these, 115 stars in 12 fields are calibrated in both ranges. O ne further field, Mrk 421, was calibrated, but on close examination all sou rces were found to be probably nonstellar; thus these results are not inclu ded here. The stars observed cover the range from V = 11 to V = 20 and from K = 9 to K = 17 and are well distributed around the sky north of declinati on -30 degrees. This represents the initial sample of an extensive catalog of calibrated fields that will cover the northern sky down to declination 3 0 degrees and that will cover a wide range of Galactic latitudes. These fie lds will be useful both for photometry of AGNs in the range from B to K and also as faint calibration standards for large telescopes. The median absol ute total error on the photometry, including all known error sources, range s from 0.008 mag in J to 0.034 mag in B. These errors will be greatly reduc ed with the addition of further data in the future, although the final prec ision is fundamentally limited by the photometric errors in the existing li sts of calibration stars used to calibrate these data.