SIMBAD references

Photometric calibration to level is frequently needed at arbitrary celestial location. However, existing all-sky astronomical catalogs do not reach this accuracy, and time consuming photometric calibration procedures are required. I fitted the Hipparcos and magnitudes, along with the 2MASS,, and magnitudes of Tycho-2-catalog stars with stellar spectral templates. From the best-fit spectral template derived for each star, I calculated its synthetic SDSS magnitudes and constructed an all-sky catalog of magnitudes of bright stars . Testing this method on SDSS photometric-telescope observations, I find that the photometric accuracy, for a single star, is usually about 0.12, 0.12, 0.10, and 0.08 mag (1 σ), for the,,, and -bands, respectively. However, by using such stars, the typical errors per calibrated field can be reduced to about 0.04, 0.03, 0.02, and 0.02 mag, in the,,, and -bands, respectively. Therefore, in cases for which several calibration stars can be observed in the field of view of an instrument, accurate photometric calibration is possible.