2010PASP..122.1437P

We present fitted and magnitudes, spectral types, and distances for 2.4 million stars, derived from synthetic photometry of a library spectrum that best matches the Tycho2, NOMAD, and 2MASS catalog magnitudes. We present similarly synthesized multifilter magnitudes, types, and distances for 4.8 million stars with 2MASS and SDSS photometry to within the Sloan survey region, for Landolt and Sloan primary standards, and for Sloan northern (photometric telescope) and southern secondary standards. The synthetic magnitude zero points for,,,,, Stromgren, Sloan, and are calibrated on 20 CALSPEC spectrophotometric standards. The and zero points have dispersions of 1-3%, for standards covering a range of color from; those for other filters are in the range of 2-5%. The spectrally matched fits to Tycho2 stars provide estimated 1σ errors per star of, 0.15, 0.12, 0.10, and 0.08 mag, respectively, in either or; those for at least 70% of the SDSS survey region to have estimated 1σ errors per star of, 0.06, 0.04, 0.04, and 0.05 in or. The density of Tycho2 stars, averaging about 60 stars per square degree, provides sufficient stars to enable automatic flux calibrations for most digital images with fields of view of 0.5° or more. Using several such standards per field, automatic flux calibration can be achieved to a few percent in any filter, at any air mass, in most workable observing conditions, to facilitate intercomparison of data from different sites, telescopes, and instruments.