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 CVnIdwA images, the average parameters for UBV are 
the following:
Airmass---1.36, 1.47, and 1.27
Integration time (s)---1800, 900, 600
Pixel scale (arcsec)---1.134, 1.134, 1.134

# Fri 09:17:55 07-Jun-2002
begin	UFIT
	status	0	(Solution converged)
	variance	0.001494522
	stdeviation	0.03865904
	avsqerror	0.001492716
	averror		0.03863568
	avsqscatter	0.001123625
	avscatter	0.03352052
	chisqr		1.00121
	msq		0.001444704
	rms		0.03800927
	reference	mU
	fitting		(UB+BV+V)+u1+u2*XU+u3*UB+u4*UB*XU
	weights		photometric
	parameters	4
		u1	(constant)
		u2	(fit)
		u3	(constant)
		u4	(constant)
	derivatives	4
		0.1
		0.1
		0.1
		0.1
	values	4
		5.318
		0.4418046
		-0.0926
		0.
	errors	4
		0.
		0.005308605
		0.
		0.

# Fri 09:18:30 07-Jun-2002
begin	BFIT
	status	0	(Solution converged)
	variance	7.801763E-4
	stdeviation	0.02793164
	avsqerror	9.297029E-4
	averror		0.03049103
	avsqscatter	3.871530E-4
	avscatter	0.0196762
	chisqr		0.8391673
	msq		7.578855E-4
	rms		0.02752972
	reference	mB
	fitting		(BV+V)+b1+b2*XB+b3*BV+b4*BV*XB
	weights		photometric
	parameters	4
		b1	(constant)
		b2	(fit)
		b3	(constant)
		b4	(constant)
	derivatives	4
		0.1
		0.1
		0.1
		0.1
	values	4
		3.688
		0.2321994
		-0.012
		0.
	errors	4
		0.
		0.003007926
		0.
		0.

# Fri 09:18:54 07-Jun-2002
begin	VFIT
	status	0	(Solution converged)
	variance	3.488368E-4
	stdeviation	0.01867717
	avsqerror	3.607810E-4
	averror		0.01899424
	avsqscatter	1.114133E-4
	avscatter	0.01055525
	chisqr		0.9668934
	msq		3.382660E-4
	rms		0.01839201
	reference	mV
	fitting		V+v1+v2*XV+v3*BV+v4*BV*XV
	weights		photometric
	parameters	4
		v1	(constant)
		v2	(fit)
		v3	(constant)
		v4	(constant)
	derivatives	4
		0.1
		0.1
		0.1
		0.1
	values	4
		3.244
		0.1523076
		-0.0131
		0.
	errors	4
		0.
		0.001815982
		0.
		0.