n6822_ubvcalib.txt
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---1.043, 1.038, 1.037
Integration time (s)---200, 30, 30
Pixel scale (arcsec)---0.43, 0.43, 0.43
begin UFIT
status 0
parameters 2
u1
u2
derivatives 2
0.1
0.1
values 2
3.18883
-0.197586
errors 2
0.007
0.012
begin BFIT
status 0
parameters 2
b1
b2
derivatives 2
0.1
0.1
values 2
0.4841993
0.0337471
errors 2
0.0105
0.01272
begin VFIT
status 0
parameters 2
v1
v2
derivatives 2
0.1
0.1
values 2
-0.1803645
-0.0204284
errors 2
0.008
0.009
