SECONDARY PHOTOMETRIC STANDARD STARS FOR THE THUAN-GUNN AND JOHNSON-KRON-COUSINS SYSTEMS

CCD photometry is presented for 119 stars observed in the Thuan-Gunn photometric system (the passbands v g r). The sample includes 82 stars for which magnitudes in this system have not previously been published. Photometry in the Johnson-Kron-Cousins photometric system (BV or UBV) has been obtained for a subsample of 85 of the stars. Of those stars which are not primary standard stars for the Thuan-Gunn system 70 observed in Gunn r, 48 observed in Gunn g, and 37 observed in Gunn v have sufficient repeat measurements that they may be used as secondary standard stars for CCD photometry. The typical uncertainties for the magnitudes of these stars are 0.006 mag.