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---1.03, 1.015, 1.09
Integration time (s)---1800, 1800, 1200
Pixel scale (arcsec)---1.134, 1.134, 1.134

# Thu 13:34:26 30-May-2002
begin	IFIT
	status	0	(Solution converged)
	variance	5.811818E-4
	stdeviation	0.02410771
	avsqerror	7.253596E-4
	averror		0.0269325
	avsqscatter	1.950797E-4
	avscatter	0.01396709
	chisqr		0.8012327
	msq		5.019298E-4
	rms		0.02240379
	reference	mI
	fitting		(V-VI)+i1+i2*XI+i3*VI+i4*VI*XI
	weights		photometric
	parameters	4
		i1	(fit)
		i2	(fit)
		i3	(fit)
		i4	(constant)
	derivatives	4
		0.1
		0.1
		0.1
		0.1
	values	4
		3.704998
		0.03273072
		0.009493044
		0.
	errors	4
		0.03047706
		0.01913347
		0.007661268
		0.

# Thu 15:08:01 30-May-2002
begin	BFIT
	status	0	(Solution converged)
	variance	0.001936667
	stdeviation	0.04400757
	avsqerror	0.002694207
	averror		0.05190575
	avsqscatter	9.749284E-4
	avscatter	0.03122384
	chisqr		0.7188261
	msq		0.001852464
	rms		0.04304026
	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
		3.445
		0.2373955
		-0.022
		0.
	errors	4
		0.
		0.004757675
		0.
		0.

# Thu 15:08:50 30-May-2002
begin	VFIT
	status	0	(Solution converged)
	variance	6.346427E-4
	stdeviation	0.02519212
	avsqerror	0.001021369
	averror		0.03195886
	avsqscatter	2.419013E-4
	avscatter	0.01555318
	chisqr		0.6213648
	msq		6.070496E-4
	rms		0.02463838
	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
		3.017
		0.1283061
		0.045
		0.
	errors	4
		0.
		0.002453171
		0.
		0.

# Thu 14:43:59 11-Jul-2002
begin	UFIT
	status	0	(Solution converged)
	variance	0.008117666
	stdeviation	0.09009809
	avsqerror	0.01131639
	averror		0.1063785
	avsqscatter	0.01121088
	avscatter	0.1058815
	chisqr		0.7173374
	msq		0.007779431
	rms		0.08820108
	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
		0.514
		-0.146
		0.
	errors	4
		0.006
		0.
		0.
		0.