UBVR and UPXYZVS sequences of standard stars for the MEGA program fields along the main meridian of the Galaxy

Abstract

Abstract. Within the framework of the MEGA program devoted to the study of the main meridional section of the Galaxy, photoelectric observations have been made in the Johnson UBVR and Vilnius UPXYZVS systems to obtain photometric sequences of standard stars in a number of proper motion fields, each of 1.4 square degree size, located approximately along the main galactic meridian.The catalog of our UBVR observations includes a total of 1141 stars which provide sequences for 47 MEGA fields and for a few of other fields. Each of the sequences contains 15 to 28 stars almost uniformly distributed in the V magnitude range from 4.5 to 15.5 mag. The external rms errors of the observations are dh 0.014 for the magnitude V and ± 0.026, ± 0.012 and ± 0.016 for the color indices U-B, B-V and V-R, respectively. These standards will be used for the reduction of photographic magnitudes.In the medium-band Vilnius system, the photoelectric sequences have been established for six MEGA fields near the galactic poles, each of which consists of about 50 standards in the magnitude range 8.5 < V< 13.5 mag. The errors of the UPXYZVS magnitudes and color indices range from ± 0.008 to ± 0.020 mag, depending on the brightness of a star.The possibility of making use of these standard sequences for CCD observations is discussed.