The information on this page is an update of that presented in Dolphin (2000). The necessitation of the update is for a few reasons:

More recent observations of Omega Cen (through June 2007)
Improved versions of HSTphot to reduce the data
Improved functional forms for the fitting

The limitation of the new calibration equations is that they only consider cold (after April 1994) observations.

Contribution for 2002 HST Calibration Workshop proceedings available here.

Equations last updated July 19, 2008.

Previous equations:

WF4 Anomaly

Since SM3B (March 2002), WF4 data have suffered from what is called the "WF4 Anomaly". Further details about this can be found at STScI's WFPC2 pages, most notably ISR 0502.

From the residuals to the CTE and zero point correction solutions presented here, two key times can be located. Beginning at the time of SM3B (March 2002), an increasing number of images with low bias appeared (as has been documented well in the STScI sources referenced above). In addition, my preliminary analysis indicates a significant change to the XCTE losses at this time (perhaps tripled or more).

The second key time was the temperature reductions in the WF4 electronics that were designed to combat the anomaly. This had the effect of significantly reducing the YCTE loss (perhaps by 20%).

The photometric effects have not yet been adequately calibrated in this work, so I have omitted all WF4 data from March 2002 onwards in deriving the equations below. This means that calibration of WF4 data may not be as reliable as the other chips, even if one applies the streak and count level corrections as recommended in ISR 0502.

The remaining data (PC, WF2, and WF3) fit the lifetime curves very well, with average residuals under 1% per chip or filter, and less than 0.02 magnitudes per dex of star brightness or background level.

CTE Correction

The recommended CTE correction below is more complex than usual CTE equations, to allow for the fact that the star brightness is not constant as it is read out, and therefore that the CTE loss per pixel changes during readout. The recipe for correction is as follows:

First, calculate the following variable values:

lct0 = ln(counts/electrons) - 7
bg = sqrt ( background/electrons^2 + 1 ) - 10
lbg = ln(sqrt ( background/electrons^2 + 1 )) - 1
yr = (MJD - 50193) / 365.25

Second, correct for the CTE loss in X readout:

XCTE (mags) = 0.0075*exp(-0.037*bg)*x/800

Third, recalculate lct using:

lct = lct0 + 0.921*XCTE

Finally, correct for the CTE loss in Y readout:

c1 = 0.0542-0.01156*lbg+0.00219*lbg*lct
c1 = 0.0071 (if greater than value in previous line)
c2 = 1+0.296*yr-0.0086*yr*yr
c3 = exp(-0.377*lct)
YCTE (mags) = ln(1+c1*c2*c3*y/800)/0.347

Uncertainties of the parameters:

0.0075 +/- 0.0014
0.037 +/- 0.017
0.0542 +/- 0.0006
0.01156 +/- 0.00016
0.00219 +/- 0.00008
0.0071 +/- 0.0014
0.296 +/- 0.005
0.0086 +/- 0.0004
0.377 +/- 0.003
0.347 +/- 0.003

Note that the background level should equal the true background of the image. For a sky measured near the star, there is usually some starlight in the sky annulus that can cause confusion. For images with low background levels, this can become a major fraction of the measured background.

Also note that the choice of photometry parameters can affect the CTE solution, as CTE loss affects the PSF for very faint sources. The solution here is for the default HSTphot parameters -- a PSF-fit inside a small (3 pixel PC, 2 pixel WFC) aperture.

Zero Points relative to Holtzman et al. (1995)

GAIN=7 GAIN=14

Filter PC1 WFC2 WFC3 WFC4 PC1 WFC2 WFC3 WFC4

F439W 0.058 +/- 0.007 0.060 +/- 0.004 0.054 +/- 0.004 0.066 +/- 0.004 0.036 +/- 0.002 0.058 +/- 0.001 0.034 +/- 0.001 0.058 +/- 0.001

F555W 0.035 +/- 0.002 0.038 +/- 0.001 0.034 +/- 0.002 0.040 +/- 0.001 0.029 +/- 0.002 0.028 +/- 0.001 0.029 +/- 0.001 0.043 +/- 0.001

F675W 0.048 +/- 0.006 0.048 +/- 0.003 0.040 +/- 0.004 0.055 +/- 0.004 0.030 +/- 0.002 0.048 +/- 0.001 0.039 +/- 0.001 0.042 +/- 0.002

F814W 0.006 +/- 0.001 0.031 +/- 0.000 0.026 +/- 0.001 0.024 +/- 0.001 0.015 +/- 0.001 0.031 +/- 0.001 0.019 +/- 0.001 0.022 +/- 0.001

note: add these values to Holtzman-calibrated magnitudes

	GAIN=7	GAIN=14
Filter	PC1	WFC2	WFC3	WFC4	PC1	WFC2	WFC3	WFC4
F439W	0.058 +/- 0.007	0.060 +/- 0.004	0.054 +/- 0.004	0.066 +/- 0.004	0.036 +/- 0.002	0.058 +/- 0.001	0.034 +/- 0.001	0.058 +/- 0.001
F555W	0.035 +/- 0.002	0.038 +/- 0.001	0.034 +/- 0.002	0.040 +/- 0.001	0.029 +/- 0.002	0.028 +/- 0.001	0.029 +/- 0.001	0.043 +/- 0.001
F675W	0.048 +/- 0.006	0.048 +/- 0.003	0.040 +/- 0.004	0.055 +/- 0.004	0.030 +/- 0.002	0.048 +/- 0.001	0.039 +/- 0.001	0.042 +/- 0.002
F814W	0.006 +/- 0.001	0.031 +/- 0.000	0.026 +/- 0.001	0.024 +/- 0.001	0.015 +/- 0.001	0.031 +/- 0.001	0.019 +/- 0.001	0.022 +/- 0.001

Additional Offsets for Non-Standard Filters

Filter Std Filt offset

F300W F336W -0.000 +/- 0.000

F380W F439W 0.079 +/- 0.003

F410M F439W 0.052 +/- 0.004

F450W F439W -0.006 +/- 0.004

F467M F439W -0.068 +/- 0.003

F547M F555W -0.004 +/- 0.002

F569W F555W -0.022 +/- 0.002

F606W F555W -0.018 +/- 0.002

F622W F675W -0.015 +/- 0.005

F702W F675W 0.006 +/- 0.002

F785LP F814W 0.005 +/- 0.003

F791W F814W -0.020 +/- 0.006

F850LP F814W 0.004 +/- 0.005

F1042M F814W 0.069 +/- 0.009

note: add these values plus the corresponding calibration from the standard filter table to Holtzman-calibrated magnitudes

Filter	Std Filt	offset
F300W	F336W	-0.000 +/- 0.000
F380W	F439W	0.079 +/- 0.003
F410M	F439W	0.052 +/- 0.004
F450W	F439W	-0.006 +/- 0.004
F467M	F439W	-0.068 +/- 0.003
F547M	F555W	-0.004 +/- 0.002
F569W	F555W	-0.022 +/- 0.002
F606W	F555W	-0.018 +/- 0.002
F622W	F675W	-0.015 +/- 0.005
F702W	F675W	0.006 +/- 0.002
F785LP	F814W	0.005 +/- 0.003
F791W	F814W	-0.020 +/- 0.006
F850LP	F814W	0.004 +/- 0.005
F1042M	F814W	0.069 +/- 0.009

WFPC2 Instrumental Magnitudes

GAIN=7 Zero Points for 1 DN/sec

Filter PC1 WFC2 WFC3 WFC4
F380W 20.994 +/- 0.008 21.007 +/- 0.005 21.008 +/- 0.005 20.991 +/- 0.005

F410M 19.353 +/- 0.008 19.366 +/- 0.005 19.367 +/- 0.006 19.349 +/- 0.005

F439W 20.866 +/- 0.007 20.879 +/- 0.004 20.880 +/- 0.004 20.863 +/- 0.004

F450W 21.963 +/- 0.008 21.975 +/- 0.005 21.976 +/- 0.006 21.959 +/- 0.005

F467M 19.888 +/- 0.008 19.900 +/- 0.005 19.901 +/- 0.005 19.884 +/- 0.005

F547M 21.609 +/- 0.003 21.622 +/- 0.003 21.625 +/- 0.003 21.601 +/- 0.003

F555W 22.498 +/- 0.002 22.511 +/- 0.001 22.515 +/- 0.002 22.491 +/- 0.001

F569W 22.171 +/- 0.003 22.184 +/- 0.003 22.188 +/- 0.003 22.164 +/- 0.003

F606W 22.839 +/- 0.003 22.853 +/- 0.002 22.856 +/- 0.003 22.832 +/- 0.002

F622W 22.314 +/- 0.008 22.324 +/- 0.006 22.323 +/- 0.006 22.309 +/- 0.006

F675W 22.020 +/- 0.006 22.031 +/- 0.003 22.030 +/- 0.004 22.016 +/- 0.004

F702W 22.420 +/- 0.007 22.430 +/- 0.004 22.429 +/- 0.005 22.415 +/- 0.004

F785LP 20.626 +/- 0.003 20.662 +/- 0.003 20.664 +/- 0.003 20.633 +/- 0.003

F791W 21.431 +/- 0.006 21.467 +/- 0.006 21.469 +/- 0.006 21.438 +/- 0.006

F814W 21.583 +/- 0.001 21.619 +/- 0.000 21.621 +/- 0.001 21.590 +/- 0.001

F850LP 19.888 +/- 0.005 19.924 +/- 0.005 19.926 +/- 0.005 19.895 +/- 0.005

F1042M 16.180 +/- 0.009 16.216 +/- 0.009 16.218 +/- 0.009 16.187 +/- 0.009

Filter	PC1	WFC2	WFC3	WFC4
F380W	20.994 +/- 0.008	21.007 +/- 0.005	21.008 +/- 0.005	20.991 +/- 0.005
F410M	19.353 +/- 0.008	19.366 +/- 0.005	19.367 +/- 0.006	19.349 +/- 0.005
F439W	20.866 +/- 0.007	20.879 +/- 0.004	20.880 +/- 0.004	20.863 +/- 0.004
F450W	21.963 +/- 0.008	21.975 +/- 0.005	21.976 +/- 0.006	21.959 +/- 0.005
F467M	19.888 +/- 0.008	19.900 +/- 0.005	19.901 +/- 0.005	19.884 +/- 0.005
F547M	21.609 +/- 0.003	21.622 +/- 0.003	21.625 +/- 0.003	21.601 +/- 0.003
F555W	22.498 +/- 0.002	22.511 +/- 0.001	22.515 +/- 0.002	22.491 +/- 0.001
F569W	22.171 +/- 0.003	22.184 +/- 0.003	22.188 +/- 0.003	22.164 +/- 0.003
F606W	22.839 +/- 0.003	22.853 +/- 0.002	22.856 +/- 0.003	22.832 +/- 0.002
F622W	22.314 +/- 0.008	22.324 +/- 0.006	22.323 +/- 0.006	22.309 +/- 0.006
F675W	22.020 +/- 0.006	22.031 +/- 0.003	22.030 +/- 0.004	22.016 +/- 0.004
F702W	22.420 +/- 0.007	22.430 +/- 0.004	22.429 +/- 0.005	22.415 +/- 0.004
F785LP	20.626 +/- 0.003	20.662 +/- 0.003	20.664 +/- 0.003	20.633 +/- 0.003
F791W	21.431 +/- 0.006	21.467 +/- 0.006	21.469 +/- 0.006	21.438 +/- 0.006
F814W	21.583 +/- 0.001	21.619 +/- 0.000	21.621 +/- 0.001	21.590 +/- 0.001
F850LP	19.888 +/- 0.005	19.924 +/- 0.005	19.926 +/- 0.005	19.895 +/- 0.005
F1042M	16.180 +/- 0.009	16.216 +/- 0.009	16.218 +/- 0.009	16.187 +/- 0.009

GAIN=14 Zero Points for 1 DN/sec

Filter PC1 WFC2 WFC3 WFC4
F380W 20.227 +/- 0.004 20.251 +/- 0.004 20.232 +/- 0.004 20.254 +/- 0.004

F410M 18.586 +/- 0.004 18.610 +/- 0.004 18.591 +/- 0.004 18.613 +/- 0.004

F439W 20.099 +/- 0.002 20.123 +/- 0.001 20.104 +/- 0.001 20.126 +/- 0.001

F450W 21.196 +/- 0.004 21.220 +/- 0.004 21.201 +/- 0.004 21.223 +/- 0.004

F467M 19.121 +/- 0.004 19.145 +/- 0.003 19.126 +/- 0.003 19.148 +/- 0.003

F547M 20.857 +/- 0.003 20.857 +/- 0.002 20.865 +/- 0.003 20.877 +/- 0.003

F555W 21.747 +/- 0.002 21.747 +/- 0.001 21.754 +/- 0.001 21.767 +/- 0.001

F569W 21.420 +/- 0.003 21.420 +/- 0.002 21.427 +/- 0.003 21.439 +/- 0.003

F606W 22.088 +/- 0.003 22.088 +/- 0.002 22.095 +/- 0.002 22.108 +/- 0.002

F622W 21.550 +/- 0.006 21.571 +/- 0.005 21.567 +/- 0.005 21.568 +/- 0.005

F675W 21.257 +/- 0.002 21.277 +/- 0.001 21.273 +/- 0.001 21.274 +/- 0.002

F702W 21.656 +/- 0.003 21.677 +/- 0.002 21.673 +/- 0.003 21.674 +/- 0.003

F785LP 19.890 +/- 0.003 19.908 +/- 0.003 19.901 +/- 0.003 19.903 +/- 0.003

F791W 20.695 +/- 0.006 20.712 +/- 0.006 20.706 +/- 0.006 20.707 +/- 0.006

F814W 20.847 +/- 0.001 20.864 +/- 0.001 20.858 +/- 0.001 20.859 +/- 0.001

F850LP 19.152 +/- 0.005 19.170 +/- 0.005 19.163 +/- 0.005 19.164 +/- 0.005

F1042M 15.444 +/- 0.009 15.462 +/- 0.009 15.455 +/- 0.009 15.456 +/- 0.009

Filter	PC1	WFC2	WFC3	WFC4
F380W	20.227 +/- 0.004	20.251 +/- 0.004	20.232 +/- 0.004	20.254 +/- 0.004
F410M	18.586 +/- 0.004	18.610 +/- 0.004	18.591 +/- 0.004	18.613 +/- 0.004
F439W	20.099 +/- 0.002	20.123 +/- 0.001	20.104 +/- 0.001	20.126 +/- 0.001
F450W	21.196 +/- 0.004	21.220 +/- 0.004	21.201 +/- 0.004	21.223 +/- 0.004
F467M	19.121 +/- 0.004	19.145 +/- 0.003	19.126 +/- 0.003	19.148 +/- 0.003
F547M	20.857 +/- 0.003	20.857 +/- 0.002	20.865 +/- 0.003	20.877 +/- 0.003
F555W	21.747 +/- 0.002	21.747 +/- 0.001	21.754 +/- 0.001	21.767 +/- 0.001
F569W	21.420 +/- 0.003	21.420 +/- 0.002	21.427 +/- 0.003	21.439 +/- 0.003
F606W	22.088 +/- 0.003	22.088 +/- 0.002	22.095 +/- 0.002	22.108 +/- 0.002
F622W	21.550 +/- 0.006	21.571 +/- 0.005	21.567 +/- 0.005	21.568 +/- 0.005
F675W	21.257 +/- 0.002	21.277 +/- 0.001	21.273 +/- 0.001	21.274 +/- 0.002
F702W	21.656 +/- 0.003	21.677 +/- 0.002	21.673 +/- 0.003	21.674 +/- 0.003
F785LP	19.890 +/- 0.003	19.908 +/- 0.003	19.901 +/- 0.003	19.903 +/- 0.003
F791W	20.695 +/- 0.006	20.712 +/- 0.006	20.706 +/- 0.006	20.707 +/- 0.006
F814W	20.847 +/- 0.001	20.864 +/- 0.001	20.858 +/- 0.001	20.859 +/- 0.001
F850LP	19.152 +/- 0.005	19.170 +/- 0.005	19.163 +/- 0.005	19.164 +/- 0.005
F1042M	15.444 +/- 0.009	15.462 +/- 0.009	15.455 +/- 0.009	15.456 +/- 0.009

note: WFPC2mag = -2.5 log (DN/s) + ZP(FG) - CTE
ZP(FG) from above tables
CTE calculated from above equations

UBVRI Transformations

GAIN=7

Filter SMAG SCOL ZP(PC1) ZP(WFC2) ZP(WFC3) ZP(WFC4) T1 T2 Cmin Cmax

F380W B (B-V) 21.019 21.032 21.033 21.016 -0.581 0.777 ... 0.5

F380W B (B-V) 21.371 21.384 21.385 21.368 -0.943 0.103 0.5 ...

F410M B (B-V) 19.663 19.676 19.677 19.659 -0.183 -0.287 ... ...

F439W B (U-B) 20.853 20.866 20.867 20.850 -0.103 -0.046 ... ...

F439W B (B-V) 20.866 20.879 20.880 20.863 0.003 -0.088 ... ...

F439W B (B-R) 20.860 20.873 20.874 20.857 0.019 -0.049 ... ...

F439W B (B-I) 20.863 20.876 20.877 20.860 0.005 -0.023 ... ...

F450W B (B-V) 21.965 21.977 21.978 21.961 0.230 -0.003 ... ...

F467M B (B-V) 19.895 19.907 19.908 19.891 0.480 -0.299 ... 0.5

F467M B (B-V) 19.846 19.858 19.859 19.842 0.432 -0.002 0.5 ...

F547M V (B-V) 21.604 21.617 21.620 21.596 0.031 -0.039 ... 1.0

F547M V (B-V) 21.556 21.569 21.572 21.548 0.056 -0.016 1.0 ...

F547M V (V-I) 21.604 21.617 21.620 21.596 0.027 -0.032 ... 1.1

F547M V (V-I) 21.556 21.569 21.572 21.548 0.049 -0.013 1.1 ...

F555W V (U-V) 22.479 22.492 22.496 22.472 -0.014 0.005 ... ...

F555W V (B-V) 22.498 22.511 22.515 22.491 -0.060 0.033 ... ...

F555W V (V-R) 22.503 22.516 22.520 22.496 -0.121 0.120 ... ...

F555W V (V-I) 22.498 22.511 22.515 22.491 -0.052 0.027 ... ...

F569W V (V-I) 22.169 22.182 22.186 22.162 0.089 -0.003 ... 2.0

F569W V (V-I) 22.501 22.514 22.518 22.494 -0.125 0.022 2.0 ...

F606W V (B-V) 22.848 22.862 22.865 22.841 0.293 0.015 ... 1.7

F606W V (B-V) 23.638 23.652 23.655 23.631 -0.284 0.081 1.7 ...

F606W V (V-I) 22.848 22.862 22.865 22.841 0.254 0.012 ... 2.0

F606W V (V-I) 23.638 23.652 23.655 23.631 -0.247 0.065 2.0 ...

F622W R (V-R) 22.328 22.338 22.337 22.323 -0.252 -0.111 ... ...

F675W R (U-R) 22.040 22.051 22.050 22.036 0.039 -0.007 ... ...

F675W R (B-R) 22.021 22.032 22.031 22.017 0.092 -0.017 ... ...

F675W R (V-R) 22.020 22.031 22.030 22.016 0.253 -0.125 ... ...

F675W R (R-I) 22.011 22.022 22.021 22.007 0.273 -0.066 ... ...

F702W R (V-R) 22.425 22.435 22.434 22.420 0.343 -0.177 ... 0.6

F702W R (V-R) 22.303 22.313 22.312 22.298 0.486 -0.079 0.6 ...

F785LP I (V-I) 20.629 20.665 20.667 20.636 0.091 0.020 ... ...

F791W I (V-I) 21.431 21.467 21.469 21.438 -0.029 -0.004 ... 1.0

F791W I (V-I) 21.472 21.508 21.510 21.479 -0.084 0.011 1.0 ...

F814W I (U-I) 21.559 21.595 21.597 21.566 -0.018 0.002 ... ...

F814W I (B-I) 21.579 21.615 21.617 21.586 -0.031 0.007 ... ...

F814W I (V-I) 21.583 21.619 21.621 21.590 -0.062 0.025 ... ...

F814W I (R-I) 21.583 21.619 21.621 21.590 -0.112 0.084 ... ...

F850LP I (V-I) 19.870 19.906 19.908 19.877 0.160 0.023 ... ...

F1042M I (V-I) 16.127 16.163 16.165 16.134 0.350 0.022 ... ...

Filter	SMAG	SCOL	ZP(PC1)	ZP(WFC2)	ZP(WFC3)	ZP(WFC4)	T1	T2	Cmin	Cmax
F380W	B	(B-V)	21.019	21.032	21.033	21.016	-0.581	0.777	...	0.5
F380W	B	(B-V)	21.371	21.384	21.385	21.368	-0.943	0.103	0.5	...
F410M	B	(B-V)	19.663	19.676	19.677	19.659	-0.183	-0.287	...	...
F439W	B	(U-B)	20.853	20.866	20.867	20.850	-0.103	-0.046	...	...
F439W	B	(B-V)	20.866	20.879	20.880	20.863	0.003	-0.088	...	...
F439W	B	(B-R)	20.860	20.873	20.874	20.857	0.019	-0.049	...	...
F439W	B	(B-I)	20.863	20.876	20.877	20.860	0.005	-0.023	...	...
F450W	B	(B-V)	21.965	21.977	21.978	21.961	0.230	-0.003	...	...
F467M	B	(B-V)	19.895	19.907	19.908	19.891	0.480	-0.299	...	0.5
F467M	B	(B-V)	19.846	19.858	19.859	19.842	0.432	-0.002	0.5	...
F547M	V	(B-V)	21.604	21.617	21.620	21.596	0.031	-0.039	...	1.0
F547M	V	(B-V)	21.556	21.569	21.572	21.548	0.056	-0.016	1.0	...
F547M	V	(V-I)	21.604	21.617	21.620	21.596	0.027	-0.032	...	1.1
F547M	V	(V-I)	21.556	21.569	21.572	21.548	0.049	-0.013	1.1	...
F555W	V	(U-V)	22.479	22.492	22.496	22.472	-0.014	0.005	...	...
F555W	V	(B-V)	22.498	22.511	22.515	22.491	-0.060	0.033	...	...
F555W	V	(V-R)	22.503	22.516	22.520	22.496	-0.121	0.120	...	...
F555W	V	(V-I)	22.498	22.511	22.515	22.491	-0.052	0.027	...	...
F569W	V	(V-I)	22.169	22.182	22.186	22.162	0.089	-0.003	...	2.0
F569W	V	(V-I)	22.501	22.514	22.518	22.494	-0.125	0.022	2.0	...
F606W	V	(B-V)	22.848	22.862	22.865	22.841	0.293	0.015	...	1.7
F606W	V	(B-V)	23.638	23.652	23.655	23.631	-0.284	0.081	1.7	...
F606W	V	(V-I)	22.848	22.862	22.865	22.841	0.254	0.012	...	2.0
F606W	V	(V-I)	23.638	23.652	23.655	23.631	-0.247	0.065	2.0	...
F622W	R	(V-R)	22.328	22.338	22.337	22.323	-0.252	-0.111	...	...
F675W	R	(U-R)	22.040	22.051	22.050	22.036	0.039	-0.007	...	...
F675W	R	(B-R)	22.021	22.032	22.031	22.017	0.092	-0.017	...	...
F675W	R	(V-R)	22.020	22.031	22.030	22.016	0.253	-0.125	...	...
F675W	R	(R-I)	22.011	22.022	22.021	22.007	0.273	-0.066	...	...
F702W	R	(V-R)	22.425	22.435	22.434	22.420	0.343	-0.177	...	0.6
F702W	R	(V-R)	22.303	22.313	22.312	22.298	0.486	-0.079	0.6	...
F785LP	I	(V-I)	20.629	20.665	20.667	20.636	0.091	0.020	...	...
F791W	I	(V-I)	21.431	21.467	21.469	21.438	-0.029	-0.004	...	1.0
F791W	I	(V-I)	21.472	21.508	21.510	21.479	-0.084	0.011	1.0	...
F814W	I	(U-I)	21.559	21.595	21.597	21.566	-0.018	0.002	...	...
F814W	I	(B-I)	21.579	21.615	21.617	21.586	-0.031	0.007	...	...
F814W	I	(V-I)	21.583	21.619	21.621	21.590	-0.062	0.025	...	...
F814W	I	(R-I)	21.583	21.619	21.621	21.590	-0.112	0.084	...	...
F850LP	I	(V-I)	19.870	19.906	19.908	19.877	0.160	0.023	...	...
F1042M	I	(V-I)	16.127	16.163	16.165	16.134	0.350	0.022	...	...

GAIN=14

Filter SMAG SCOL ZP(PC1) ZP(WFC2) ZP(WFC3) ZP(WFC4) T1 T2 Cmin Cmax

F380W B (B-V) 20.252 20.276 20.257 20.279 -0.581 0.777 ... 0.5

F380W B (B-V) 20.604 20.628 20.609 20.631 -0.943 0.103 0.5 ...

F410M B (B-V) 18.896 18.920 18.901 18.923 -0.183 -0.287 ... ...

F439W B (U-B) 20.086 20.110 20.091 20.113 -0.103 -0.046 ... ...

F439W B (B-V) 20.099 20.123 20.104 20.126 0.003 -0.088 ... ...

F439W B (B-R) 20.093 20.117 20.098 20.120 0.019 -0.049 ... ...

F439W B (B-I) 20.096 20.120 20.101 20.123 0.005 -0.023 ... ...

F450W B (B-V) 21.198 21.222 21.203 21.225 0.230 -0.003 ... ...

F467M B (B-V) 19.128 19.152 19.133 19.155 0.480 -0.299 ... 0.5

F467M B (B-V) 19.079 19.103 19.084 19.106 0.432 -0.002 0.5 ...

F547M V (B-V) 20.852 20.852 20.860 20.872 0.031 -0.039 ... 1.0

F547M V (B-V) 20.804 20.804 20.812 20.824 0.056 -0.016 1.0 ...

F547M V (V-I) 20.852 20.852 20.860 20.872 0.027 -0.032 ... 1.1

F547M V (V-I) 20.804 20.804 20.812 20.824 0.049 -0.013 1.1 ...

F555W V (U-V) 21.728 21.728 21.735 21.748 -0.014 0.005 ... ...

F555W V (B-V) 21.747 21.747 21.754 21.767 -0.060 0.033 ... ...

F555W V (V-R) 21.752 21.752 21.759 21.772 -0.121 0.120 ... ...

F555W V (V-I) 21.747 21.747 21.754 21.767 -0.052 0.027 ... ...

F569W V (V-I) 21.418 21.418 21.425 21.437 0.089 -0.003 ... 2.0

F569W V (V-I) 21.750 21.750 21.757 21.769 -0.125 0.022 2.0 ...

F606W V (B-V) 22.097 22.097 22.104 22.117 0.293 0.015 ... 1.7

F606W V (B-V) 22.887 22.887 22.894 22.907 -0.284 0.081 1.7 ...

F606W V (V-I) 22.097 22.097 22.104 22.117 0.254 0.012 ... 2.0

F606W V (V-I) 22.887 22.887 22.894 22.907 -0.247 0.065 2.0 ...

F622W R (V-R) 21.564 21.585 21.581 21.582 -0.252 -0.111 ... ...

F675W R (U-R) 21.277 21.297 21.293 21.294 0.039 -0.007 ... ...

F675W R (B-R) 21.258 21.278 21.274 21.275 0.092 -0.017 ... ...

F675W R (V-R) 21.257 21.277 21.273 21.274 0.253 -0.125 ... ...

F675W R (R-I) 21.248 21.268 21.264 21.265 0.273 -0.066 ... ...

F702W R (V-R) 21.661 21.682 21.678 21.679 0.343 -0.177 ... 0.6

F702W R (V-R) 21.539 21.560 21.556 21.557 0.486 -0.079 0.6 ...

F785LP I (V-I) 19.893 19.911 19.904 19.906 0.091 0.020 ... ...

F791W I (V-I) 20.695 20.712 20.706 20.707 -0.029 -0.004 ... 1.0

F791W I (V-I) 20.736 20.753 20.747 20.748 -0.084 0.011 1.0 ...

F814W I (U-I) 20.823 20.840 20.834 20.835 -0.018 0.002 ... ...

F814W I (B-I) 20.843 20.860 20.854 20.855 -0.031 0.007 ... ...

F814W I (V-I) 20.847 20.864 20.858 20.859 -0.062 0.025 ... ...

F814W I (R-I) 20.847 20.864 20.858 20.859 -0.112 0.084 ... ...

F850LP I (V-I) 19.134 19.152 19.145 19.146 0.160 0.023 ... ...

F1042M I (V-I) 15.391 15.409 15.402 15.403 0.350 0.022 ... ...

Filter	SMAG	SCOL	ZP(PC1)	ZP(WFC2)	ZP(WFC3)	ZP(WFC4)	T1	T2	Cmin	Cmax
F380W	B	(B-V)	20.252	20.276	20.257	20.279	-0.581	0.777	...	0.5
F380W	B	(B-V)	20.604	20.628	20.609	20.631	-0.943	0.103	0.5	...
F410M	B	(B-V)	18.896	18.920	18.901	18.923	-0.183	-0.287	...	...
F439W	B	(U-B)	20.086	20.110	20.091	20.113	-0.103	-0.046	...	...
F439W	B	(B-V)	20.099	20.123	20.104	20.126	0.003	-0.088	...	...
F439W	B	(B-R)	20.093	20.117	20.098	20.120	0.019	-0.049	...	...
F439W	B	(B-I)	20.096	20.120	20.101	20.123	0.005	-0.023	...	...
F450W	B	(B-V)	21.198	21.222	21.203	21.225	0.230	-0.003	...	...
F467M	B	(B-V)	19.128	19.152	19.133	19.155	0.480	-0.299	...	0.5
F467M	B	(B-V)	19.079	19.103	19.084	19.106	0.432	-0.002	0.5	...
F547M	V	(B-V)	20.852	20.852	20.860	20.872	0.031	-0.039	...	1.0
F547M	V	(B-V)	20.804	20.804	20.812	20.824	0.056	-0.016	1.0	...
F547M	V	(V-I)	20.852	20.852	20.860	20.872	0.027	-0.032	...	1.1
F547M	V	(V-I)	20.804	20.804	20.812	20.824	0.049	-0.013	1.1	...
F555W	V	(U-V)	21.728	21.728	21.735	21.748	-0.014	0.005	...	...
F555W	V	(B-V)	21.747	21.747	21.754	21.767	-0.060	0.033	...	...
F555W	V	(V-R)	21.752	21.752	21.759	21.772	-0.121	0.120	...	...
F555W	V	(V-I)	21.747	21.747	21.754	21.767	-0.052	0.027	...	...
F569W	V	(V-I)	21.418	21.418	21.425	21.437	0.089	-0.003	...	2.0
F569W	V	(V-I)	21.750	21.750	21.757	21.769	-0.125	0.022	2.0	...
F606W	V	(B-V)	22.097	22.097	22.104	22.117	0.293	0.015	...	1.7
F606W	V	(B-V)	22.887	22.887	22.894	22.907	-0.284	0.081	1.7	...
F606W	V	(V-I)	22.097	22.097	22.104	22.117	0.254	0.012	...	2.0
F606W	V	(V-I)	22.887	22.887	22.894	22.907	-0.247	0.065	2.0	...
F622W	R	(V-R)	21.564	21.585	21.581	21.582	-0.252	-0.111	...	...
F675W	R	(U-R)	21.277	21.297	21.293	21.294	0.039	-0.007	...	...
F675W	R	(B-R)	21.258	21.278	21.274	21.275	0.092	-0.017	...	...
F675W	R	(V-R)	21.257	21.277	21.273	21.274	0.253	-0.125	...	...
F675W	R	(R-I)	21.248	21.268	21.264	21.265	0.273	-0.066	...	...
F702W	R	(V-R)	21.661	21.682	21.678	21.679	0.343	-0.177	...	0.6
F702W	R	(V-R)	21.539	21.560	21.556	21.557	0.486	-0.079	0.6	...
F785LP	I	(V-I)	19.893	19.911	19.904	19.906	0.091	0.020	...	...
F791W	I	(V-I)	20.695	20.712	20.706	20.707	-0.029	-0.004	...	1.0
F791W	I	(V-I)	20.736	20.753	20.747	20.748	-0.084	0.011	1.0	...
F814W	I	(U-I)	20.823	20.840	20.834	20.835	-0.018	0.002	...	...
F814W	I	(B-I)	20.843	20.860	20.854	20.855	-0.031	0.007	...	...
F814W	I	(V-I)	20.847	20.864	20.858	20.859	-0.062	0.025	...	...
F814W	I	(R-I)	20.847	20.864	20.858	20.859	-0.112	0.084	...	...
F850LP	I	(V-I)	19.134	19.152	19.145	19.146	0.160	0.023	...	...
F1042M	I	(V-I)	15.391	15.409	15.402	15.403	0.350	0.022	...	...

note: SMAG = -2.5 log (DN/s) + ZP(FS) + T1 SCOL + T2 SCOL^2 - CTE
ZP(FS), T1, and T2 from above tables
CTE calculated from above equations

References

"The Charge Transfer Efficiency and Calibration of WFPC2." Dolphin, 2000, A. E. PASP, 112, 1397

"WFPC2 Stellar Photometry with HSTphot." Dolphin, A. E. 2000, PASP, 112, 1383