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---1.21, 1.1, 1.02
Integration time (s)---1800, 1800, 1200
Pixel scale (arcsec)---1.134, 1.134, 1.134

# Thu 17:20:41 30-May-2002
begin	BFIT
	status	0	(Solution converged)
	variance	4.372309E-4
	stdeviation	0.02091007
	avsqerror	4.372054E-4
	averror		0.02090946
	avsqscatter	2.408567E-4
	avscatter	0.01551956
	chisqr		1.000058
	msq		4.254139E-4
	rms		0.02062557
	reference	m1
	fitting		(BV+V)+b1+b2*X1+b3*BV+b4*BV*X1
	weights		photometric
	parameters	4
		b1	(constant)
		b2	(fit)
		b3	(constant)
		b4	(constant)
	derivatives	4
		0.1
		0.1
		0.1
		0.1
	values	4
		3.434
		0.3580121
		-0.0157
		0.
	errors	4
		0.
		0.002294579
		0.
		0.

# Thu 17:21:33 30-May-2002
begin	VFIT
	status	0	(Solution converged)
	variance	4.425460E-4
	stdeviation	0.02103678
	avsqerror	4.413327E-4
	averror		0.02100792
	avsqscatter	2.547749E-4
	avscatter	0.01596167
	chisqr		1.002749
	msq		4.311987E-4
	rms		0.02076532
	reference	m2
	fitting		V+v1+v2*X2+v3*BV+v4*BV*X2
	weights		photometric
	parameters	4
		v1	(constant)
		v2	(fit)
		v3	(constant)
		v4	(constant)
	derivatives	4
		0.1
		0.1
		0.1
		0.1
	values	4
		3.009
		0.2203408
		0.0415
		0.
	errors	4
		0.
		0.002178262
		0.
		0.

# Thu 14:43:04 11-Jul-2002
begin	UFIT
	status	0	(Solution converged)
	variance	0.003427509
	stdeviation	0.05854493
	avsqerror	0.00342573
	averror		0.05852973
	avsqscatter	0.002963565
	avscatter	0.05443863
	chisqr		1.000519
	msq		0.00332958
	rms		0.05770252
	reference	mU
	fitting		(UB+BV+V)+u1+u2*XU+u3*BV+u4*UB*XU
	weights		photometric
	parameters	4
		u1	(fit)
		u2	(constant)
		u3	(constant)
		u4	(constant)
	derivatives	4
		0.1
		0.1
		0.1
		0.1
	values	4
		5.065
		0.562
		-0.146
		0.
	errors	4
		0.006
		0.
		0.
		0.