Photometric standard stars in the BVI system in a wide field centered on the spiral galaxy NGC 300

Abstract

Based on 13 nights of observations of four fields in NGC 300, we have set up an extensive sequence of stars with accurate BVI photometry covering a relatively large (25 x 25 arcmin) region centered on this galaxy. This sequence of standard stars is very useful for calibrating the photometry of variable stars and other objects in NGC 300 and other galaxies obtained from wide field mosaic images. Our standard star list contains B, V and I measurements for 390 stars. The accuracy of the zero points in the V filter and B-V color is better than 0.02 mag, and about 0.03 mag for the V-I color. We found very good agreement between our measurements and those previously obtained by Walker for 26 stars near NGC 300.