SIMBAD references

The first goal of the photometric part of the MEGA program is the establishment of the sequences of standard magnitudes and color indices by a photoelectric method. From 1984 to 1991, more than 7500 photoelectric UBVR observations of 1141 stars of 4-15.5 magnitudes were carried out at three observatories. The method of reduction of the observations is described. It takes into account color equations between the instrumental and standard magnitudes and colors, the atmospheric extinction and changes of the photometer sensitivity. The accuracy of the photometric data in the final catalog is estimated.