The following calibration format can be used directly in IRAF.digiphot.photcal.invertfit. The instrumental magnitudes mU, mB, and mV are -2.5*log(counts/s)+25. For the these images, the average parameters for UBV are the following: Airmass---1.28, 1.21, 1.3 Integration time (s)---1200, 663, 600 Pixel scale (arcsec)---0.39, 0.39, 0.39 # Tue 10:58:06 01-Jul-97 begin UFIT status 0 (Solution converged) variance 0.002871941 stdeviation 0.0535905 avsqerror 0.00346484 averror 0.05886289 avsqscatter 0.002937974 avscatter 0.05420309 chisqr 0.8288814 msq 0.002735182 rms 0.05229897 reference m01 fitting (UB+BV+V)+u1+u2*X01+u3*UB+u4*T01*X01+u5*UB*UB weights photometric parameters 5 u1 (constant) u2 (fit) u3 (constant) u4 (constant) u5 (constant) derivatives 5 0.1 0.1 0.1 0.1 0.1 values 5 5.346 0.5326004 -0.102 0. 0. errors 5 0. 0.01048708 0. 0. 0. # Tue 12:26:31 01-Jul-97 begin BFIT status 0 (Solution converged) variance 1.120210E-4 stdeviation 0.010584 avsqerror 1.136157E-4 averror 0.01065907 avsqscatter 3.058562E-5 avscatter 0.005530426 chisqr 0.9859638 msq 1.064199E-4 rms 0.010316 reference m02 fitting (BV+V)+b1+b2*X02+b3*BV+b4*T01*X02 weights photometric parameters 4 b1 (constant) b2 (fit) b3 (constant) b4 (constant) derivatives 4 0.1 0.1 0.1 0.1 values 4 3.762 0.267467 -0.081 0. errors 4 0. 0.001693021 0. 0. # Tue 11:44:32 01-Jul-97 begin VFIT status 0 (Solution converged) variance 5.566568E-4 stdeviation 0.02359357 avsqerror 7.157913E-4 averror 0.02675428 avsqscatter 5.489773E-4 avscatter 0.02343027 chisqr 0.7776803 msq 5.313542E-4 rms 0.02305112 reference m03 fitting V+v1+v2*X03+v3*BV+v4*T01*X03 weights photometric parameters 4 v1 (constant) v2 (fit) v3 (constant) v4 (constant) derivatives 4 0.1 0.1 0.1 0.1 values 4 3.803 0.1939579 0.0416 0. errors 4 0. 0.004289019 0. 0.