BVRI CCD-photometry of comparison stars in the fields of galaxies with active nuclei. IV.

We report observations of 24 stars in the fields of the three Seyfert galaxies MCG +08-23-067, Mrk 817, and Mrk 290. The observations were made with a CCD array photometer in the BVRcIc bands. The V magnitudes of the observed stars ranged from 13.5 and 17.2. For stars of approximate magnitude 15, the typical photometric errors are 0.010, 0.011, 0.008 and 0.011 magnitude in the BVRI bands, respectively. The BVRI magnitudes of all these stars were not known previously. In the field of the galaxy Mrk 290 a star has been found that probably has a periodic brightness variation with P=1.518 days and the mean value V=14.80 and which may belong to the class of “spotted” stars. 14′x14′ charts are supplied for identifying the stars. These results can be used for differential photometry of active galactic nuclei in the BVRI bands. [ABSTRACT FROM AUTHOR]