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 May 12, 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) = 0.0162*exp(-0.000*bg)*x/800

Third, recalculate lct using:

lct = lct0 + 0.921*XCTE

Finally, correct for the CTE loss in Y readout:

c1 = 0.0069*(0.769*exp(-0.261*lbg)+0.231*exp(-0.0316*bg))*(1.+0.327*yr-0.0089*yr*yr)*y/800
c2 = 6.77*exp(-0.445*lct)
YCTE (mags) = ln(exp(c1)*(1+c2)-c2)/0.410

Uncertainties of the parameters:

0.0162 +/- 0.0011
0.000 +/- 0.000
0.0069 +/- 0.0005
0.769,0.231 +/- 0.024
0.261 +/- 0.008
0.0316 +/- 0.0040
0.327 +/- 0.003
0.0089 +/- 0.0002
6.77 +/- 0.55
0.445 +/- 0.005
0.410 +/- 0.004

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 roughly constant, 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. Using smaller apertures appears to increase the X-CTE to approximately 0.022*x/800 (with a minimal background dependence).

Zero Points relative to Holtzman et al. (1995)

GAIN=7 GAIN=14

Filter PC1 WFC2 WFC3 WFC4 PC1 WFC2 WFC3 WFC4

F439W 0.055 +/- 0.007 0.057 +/- 0.004 0.050 +/- 0.004 0.063 +/- 0.004 0.036 +/- 0.002 0.057 +/- 0.001 0.033 +/- 0.001 0.056 +/- 0.002

F555W 0.033 +/- 0.002 0.037 +/- 0.001 0.034 +/- 0.002 0.039 +/- 0.001 0.028 +/- 0.002 0.027 +/- 0.001 0.028 +/- 0.001 0.042 +/- 0.001

F675W 0.047 +/- 0.005 0.051 +/- 0.003 0.043 +/- 0.004 0.057 +/- 0.004 0.028 +/- 0.002 0.048 +/- 0.001 0.037 +/- 0.001 0.040 +/- 0.002

F814W 0.006 +/- 0.002 0.031 +/- 0.001 0.026 +/- 0.001 0.025 +/- 0.001 0.014 +/- 0.001 0.027 +/- 0.001 0.016 +/- 0.001 0.020 +/- 0.001

note: add these values to Holtzman-calibrated magnitudes

	GAIN=7	GAIN=14
Filter	PC1	WFC2	WFC3	WFC4	PC1	WFC2	WFC3	WFC4
F439W	0.055 +/- 0.007	0.057 +/- 0.004	0.050 +/- 0.004	0.063 +/- 0.004	0.036 +/- 0.002	0.057 +/- 0.001	0.033 +/- 0.001	0.056 +/- 0.002
F555W	0.033 +/- 0.002	0.037 +/- 0.001	0.034 +/- 0.002	0.039 +/- 0.001	0.028 +/- 0.002	0.027 +/- 0.001	0.028 +/- 0.001	0.042 +/- 0.001
F675W	0.047 +/- 0.005	0.051 +/- 0.003	0.043 +/- 0.004	0.057 +/- 0.004	0.028 +/- 0.002	0.048 +/- 0.001	0.037 +/- 0.001	0.040 +/- 0.002
F814W	0.006 +/- 0.002	0.031 +/- 0.001	0.026 +/- 0.001	0.025 +/- 0.001	0.014 +/- 0.001	0.027 +/- 0.001	0.016 +/- 0.001	0.020 +/- 0.001

Additional Offsets for Non-Standard Filters

Filter Std Filt offset

F300W F336W -0.000 +/- 0.000

F380W F439W 0.077 +/- 0.004

F410M F439W 0.051 +/- 0.004

F450W F439W -0.007 +/- 0.004

F467M F439W -0.068 +/- 0.003

F547M F555W -0.005 +/- 0.002

F569W F555W -0.022 +/- 0.003

F606W F555W -0.017 +/- 0.002

F622W F675W -0.016 +/- 0.006

F702W F675W 0.005 +/- 0.002

F785LP F814W 0.006 +/- 0.003

F791W F814W -0.020 +/- 0.005

F850LP F814W 0.006 +/- 0.006

F1042M F814W -0.000 +/- 0.000

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	0.077 +/- 0.004
F410M	F439W	0.051 +/- 0.004
F450W	F439W	-0.007 +/- 0.004
F467M	F439W	-0.068 +/- 0.003
F547M	F555W	-0.005 +/- 0.002
F569W	F555W	-0.022 +/- 0.003
F606W	F555W	-0.017 +/- 0.002
F622W	F675W	-0.016 +/- 0.006
F702W	F675W	0.005 +/- 0.002
F785LP	F814W	0.006 +/- 0.003
F791W	F814W	-0.020 +/- 0.005
F850LP	F814W	0.006 +/- 0.006
F1042M	F814W	-0.000 +/- 0.000

WFPC2 Instrumental Magnitudes

GAIN=7 Zero Points for 1 DN/sec

Filter PC1 WFC2 WFC3 WFC4
F380W 20.990 +/- 0.008 21.002 +/- 0.006 21.003 +/- 0.006 20.986 +/- 0.005

F410M 19.350 +/- 0.008 19.362 +/- 0.006 19.362 +/- 0.006 19.346 +/- 0.006

F439W 20.864 +/- 0.007 20.875 +/- 0.004 20.876 +/- 0.004 20.860 +/- 0.004

F450W 21.960 +/- 0.008 21.972 +/- 0.006 21.972 +/- 0.006 21.956 +/- 0.005

F467M 19.886 +/- 0.008 19.898 +/- 0.005 19.898 +/- 0.005 19.882 +/- 0.005

F547M 21.606 +/- 0.003 21.621 +/- 0.003 21.624 +/- 0.003 21.600 +/- 0.003

F555W 22.497 +/- 0.002 22.511 +/- 0.001 22.515 +/- 0.002 22.491 +/- 0.001

F569W 22.168 +/- 0.004 22.183 +/- 0.003 22.186 +/- 0.003 22.162 +/- 0.003

F606W 22.839 +/- 0.003 22.853 +/- 0.002 22.856 +/- 0.003 22.833 +/- 0.002

F622W 22.313 +/- 0.008 22.327 +/- 0.007 22.326 +/- 0.007 22.310 +/- 0.007

F675W 22.020 +/- 0.005 22.034 +/- 0.003 22.033 +/- 0.004 22.017 +/- 0.004

F702W 22.419 +/- 0.006 22.434 +/- 0.004 22.433 +/- 0.005 22.417 +/- 0.004

F785LP 20.627 +/- 0.003 20.662 +/- 0.003 20.665 +/- 0.003 20.634 +/- 0.003

F791W 21.432 +/- 0.005 21.467 +/- 0.005 21.469 +/- 0.005 21.438 +/- 0.005

F814W 21.584 +/- 0.002 21.619 +/- 0.001 21.621 +/- 0.001 21.590 +/- 0.001

F850LP 19.890 +/- 0.006 19.925 +/- 0.006 19.927 +/- 0.006 19.897 +/- 0.006

F1042M 16.112 +/- 0.002 16.147 +/- 0.001 16.149 +/- 0.001 16.118 +/- 0.001

Filter	PC1	WFC2	WFC3	WFC4
F380W	20.990 +/- 0.008	21.002 +/- 0.006	21.003 +/- 0.006	20.986 +/- 0.005
F410M	19.350 +/- 0.008	19.362 +/- 0.006	19.362 +/- 0.006	19.346 +/- 0.006
F439W	20.864 +/- 0.007	20.875 +/- 0.004	20.876 +/- 0.004	20.860 +/- 0.004
F450W	21.960 +/- 0.008	21.972 +/- 0.006	21.972 +/- 0.006	21.956 +/- 0.005
F467M	19.886 +/- 0.008	19.898 +/- 0.005	19.898 +/- 0.005	19.882 +/- 0.005
F547M	21.606 +/- 0.003	21.621 +/- 0.003	21.624 +/- 0.003	21.600 +/- 0.003
F555W	22.497 +/- 0.002	22.511 +/- 0.001	22.515 +/- 0.002	22.491 +/- 0.001
F569W	22.168 +/- 0.004	22.183 +/- 0.003	22.186 +/- 0.003	22.162 +/- 0.003
F606W	22.839 +/- 0.003	22.853 +/- 0.002	22.856 +/- 0.003	22.833 +/- 0.002
F622W	22.313 +/- 0.008	22.327 +/- 0.007	22.326 +/- 0.007	22.310 +/- 0.007
F675W	22.020 +/- 0.005	22.034 +/- 0.003	22.033 +/- 0.004	22.017 +/- 0.004
F702W	22.419 +/- 0.006	22.434 +/- 0.004	22.433 +/- 0.005	22.417 +/- 0.004
F785LP	20.627 +/- 0.003	20.662 +/- 0.003	20.665 +/- 0.003	20.634 +/- 0.003
F791W	21.432 +/- 0.005	21.467 +/- 0.005	21.469 +/- 0.005	21.438 +/- 0.005
F814W	21.584 +/- 0.002	21.619 +/- 0.001	21.621 +/- 0.001	21.590 +/- 0.001
F850LP	19.890 +/- 0.006	19.925 +/- 0.006	19.927 +/- 0.006	19.897 +/- 0.006
F1042M	16.112 +/- 0.002	16.147 +/- 0.001	16.149 +/- 0.001	16.118 +/- 0.001

GAIN=14 Zero Points for 1 DN/sec

Filter PC1 WFC2 WFC3 WFC4
F380W 20.225 +/- 0.004 20.248 +/- 0.004 20.229 +/- 0.004 20.251 +/- 0.004

F410M 18.585 +/- 0.005 18.608 +/- 0.004 18.589 +/- 0.004 18.610 +/- 0.004

F439W 20.099 +/- 0.002 20.122 +/- 0.001 20.103 +/- 0.001 20.124 +/- 0.002

F450W 21.195 +/- 0.004 21.218 +/- 0.004 21.199 +/- 0.004 21.221 +/- 0.004

F467M 19.121 +/- 0.004 19.144 +/- 0.003 19.125 +/- 0.003 19.147 +/- 0.003

F547M 20.856 +/- 0.003 20.856 +/- 0.003 20.862 +/- 0.003 20.875 +/- 0.003

F555W 21.746 +/- 0.002 21.747 +/- 0.001 21.753 +/- 0.001 21.765 +/- 0.001

F569W 21.418 +/- 0.003 21.418 +/- 0.003 21.424 +/- 0.003 21.437 +/- 0.003

F606W 22.088 +/- 0.003 22.088 +/- 0.002 22.095 +/- 0.002 22.107 +/- 0.002

F622W 21.548 +/- 0.006 21.569 +/- 0.006 21.564 +/- 0.006 21.565 +/- 0.006

F675W 21.255 +/- 0.002 21.276 +/- 0.001 21.271 +/- 0.001 21.273 +/- 0.002

F702W 21.654 +/- 0.003 21.676 +/- 0.003 21.670 +/- 0.003 21.672 +/- 0.003

F785LP 19.890 +/- 0.003 19.905 +/- 0.003 19.898 +/- 0.003 19.902 +/- 0.003

F791W 20.694 +/- 0.005 20.709 +/- 0.005 20.703 +/- 0.005 20.706 +/- 0.005

F814W 20.846 +/- 0.001 20.861 +/- 0.001 20.855 +/- 0.001 20.858 +/- 0.001

F850LP 19.153 +/- 0.006 19.167 +/- 0.006 19.161 +/- 0.006 19.164 +/- 0.006

F1042M 15.374 +/- 0.001 15.389 +/- 0.001 15.383 +/- 0.001 15.386 +/- 0.001

Filter	PC1	WFC2	WFC3	WFC4
F380W	20.225 +/- 0.004	20.248 +/- 0.004	20.229 +/- 0.004	20.251 +/- 0.004
F410M	18.585 +/- 0.005	18.608 +/- 0.004	18.589 +/- 0.004	18.610 +/- 0.004
F439W	20.099 +/- 0.002	20.122 +/- 0.001	20.103 +/- 0.001	20.124 +/- 0.002
F450W	21.195 +/- 0.004	21.218 +/- 0.004	21.199 +/- 0.004	21.221 +/- 0.004
F467M	19.121 +/- 0.004	19.144 +/- 0.003	19.125 +/- 0.003	19.147 +/- 0.003
F547M	20.856 +/- 0.003	20.856 +/- 0.003	20.862 +/- 0.003	20.875 +/- 0.003
F555W	21.746 +/- 0.002	21.747 +/- 0.001	21.753 +/- 0.001	21.765 +/- 0.001
F569W	21.418 +/- 0.003	21.418 +/- 0.003	21.424 +/- 0.003	21.437 +/- 0.003
F606W	22.088 +/- 0.003	22.088 +/- 0.002	22.095 +/- 0.002	22.107 +/- 0.002
F622W	21.548 +/- 0.006	21.569 +/- 0.006	21.564 +/- 0.006	21.565 +/- 0.006
F675W	21.255 +/- 0.002	21.276 +/- 0.001	21.271 +/- 0.001	21.273 +/- 0.002
F702W	21.654 +/- 0.003	21.676 +/- 0.003	21.670 +/- 0.003	21.672 +/- 0.003
F785LP	19.890 +/- 0.003	19.905 +/- 0.003	19.898 +/- 0.003	19.902 +/- 0.003
F791W	20.694 +/- 0.005	20.709 +/- 0.005	20.703 +/- 0.005	20.706 +/- 0.005
F814W	20.846 +/- 0.001	20.861 +/- 0.001	20.855 +/- 0.001	20.858 +/- 0.001
F850LP	19.153 +/- 0.006	19.167 +/- 0.006	19.161 +/- 0.006	19.164 +/- 0.006
F1042M	15.374 +/- 0.001	15.389 +/- 0.001	15.383 +/- 0.001	15.386 +/- 0.001

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) 21.015 21.027 21.028 21.011 -0.581 0.777 ... 0.5

F380W B (B-V) 21.367 21.379 21.380 21.363 -0.943 0.103 0.5 ...

F410M B (B-V) 19.660 19.672 19.672 19.656 -0.183 -0.287 ... ...

F439W B (U-B) 20.851 20.862 20.863 20.847 -0.103 -0.046 ... ...

F439W B (B-V) 20.864 20.875 20.876 20.860 0.003 -0.088 ... ...

F439W B (B-R) 20.858 20.869 20.870 20.854 0.019 -0.049 ... ...

F439W B (B-I) 20.861 20.872 20.873 20.857 0.005 -0.023 ... ...

F450W B (B-V) 21.962 21.974 21.974 21.958 0.230 -0.003 ... ...

F467M B (B-V) 19.893 19.905 19.905 19.889 0.480 -0.299 ... 0.5

F467M B (B-V) 19.844 19.856 19.856 19.840 0.432 -0.002 0.5 ...

F547M V (B-V) 21.601 21.616 21.619 21.595 0.031 -0.039 ... 1.0

F547M V (B-V) 21.553 21.568 21.571 21.547 0.056 -0.016 1.0 ...

F547M V (V-I) 21.601 21.616 21.619 21.595 0.027 -0.032 ... 1.1

F547M V (V-I) 21.553 21.568 21.571 21.547 0.049 -0.013 1.1 ...

F555W V (U-V) 22.478 22.492 22.496 22.472 -0.014 0.005 ... ...

F555W V (B-V) 22.497 22.511 22.515 22.491 -0.060 0.033 ... ...

F555W V (V-R) 22.502 22.516 22.520 22.496 -0.121 0.120 ... ...

F555W V (V-I) 22.497 22.511 22.515 22.491 -0.052 0.027 ... ...

F569W V (V-I) 22.166 22.181 22.184 22.160 0.089 -0.003 ... 2.0

F569W V (V-I) 22.498 22.513 22.516 22.492 -0.125 0.022 2.0 ...

F606W V (B-V) 22.848 22.862 22.865 22.842 0.293 0.015 ... 1.7

F606W V (B-V) 23.638 23.652 23.655 23.632 -0.284 0.081 1.7 ...

F606W V (V-I) 22.848 22.862 22.865 22.842 0.254 0.012 ... 2.0

F606W V (V-I) 23.638 23.652 23.655 23.632 -0.247 0.065 2.0 ...

F622W R (V-R) 22.327 22.341 22.340 22.324 -0.252 -0.111 ... ...

F675W R (U-R) 22.040 22.054 22.053 22.037 0.039 -0.007 ... ...

F675W R (B-R) 22.021 22.035 22.034 22.018 0.092 -0.017 ... ...

F675W R (V-R) 22.020 22.034 22.033 22.017 0.253 -0.125 ... ...

F675W R (R-I) 22.011 22.025 22.024 22.008 0.273 -0.066 ... ...

F702W R (V-R) 22.424 22.439 22.438 22.422 0.343 -0.177 ... 0.6

F702W R (V-R) 22.302 22.317 22.316 22.300 0.486 -0.079 0.6 ...

F785LP I (V-I) 20.630 20.665 20.668 20.637 0.091 0.020 ... ...

F791W I (V-I) 21.432 21.467 21.469 21.438 -0.029 -0.004 ... 1.0

F791W I (V-I) 21.473 21.508 21.510 21.479 -0.084 0.011 1.0 ...

F814W I (U-I) 21.560 21.595 21.597 21.566 -0.018 0.002 ... ...

F814W I (B-I) 21.580 21.615 21.617 21.586 -0.031 0.007 ... ...

F814W I (V-I) 21.584 21.619 21.621 21.590 -0.062 0.025 ... ...

F814W I (R-I) 21.584 21.619 21.621 21.590 -0.112 0.084 ... ...

F850LP I (V-I) 19.872 19.907 19.909 19.879 0.160 0.023 ... ...

F1042M I (V-I) 16.059 16.094 16.096 16.065 0.350 0.022 ... ...

Filter	SMAG	SCOL	ZP(PC1)	ZP(WFC2)	ZP(WFC3)	ZP(WFC4)	T1	T2	Cmin	Cmax
F380W	B	(B-V)	21.015	21.027	21.028	21.011	-0.581	0.777	...	0.5
F380W	B	(B-V)	21.367	21.379	21.380	21.363	-0.943	0.103	0.5	...
F410M	B	(B-V)	19.660	19.672	19.672	19.656	-0.183	-0.287	...	...
F439W	B	(U-B)	20.851	20.862	20.863	20.847	-0.103	-0.046	...	...
F439W	B	(B-V)	20.864	20.875	20.876	20.860	0.003	-0.088	...	...
F439W	B	(B-R)	20.858	20.869	20.870	20.854	0.019	-0.049	...	...
F439W	B	(B-I)	20.861	20.872	20.873	20.857	0.005	-0.023	...	...
F450W	B	(B-V)	21.962	21.974	21.974	21.958	0.230	-0.003	...	...
F467M	B	(B-V)	19.893	19.905	19.905	19.889	0.480	-0.299	...	0.5
F467M	B	(B-V)	19.844	19.856	19.856	19.840	0.432	-0.002	0.5	...
F547M	V	(B-V)	21.601	21.616	21.619	21.595	0.031	-0.039	...	1.0
F547M	V	(B-V)	21.553	21.568	21.571	21.547	0.056	-0.016	1.0	...
F547M	V	(V-I)	21.601	21.616	21.619	21.595	0.027	-0.032	...	1.1
F547M	V	(V-I)	21.553	21.568	21.571	21.547	0.049	-0.013	1.1	...
F555W	V	(U-V)	22.478	22.492	22.496	22.472	-0.014	0.005	...	...
F555W	V	(B-V)	22.497	22.511	22.515	22.491	-0.060	0.033	...	...
F555W	V	(V-R)	22.502	22.516	22.520	22.496	-0.121	0.120	...	...
F555W	V	(V-I)	22.497	22.511	22.515	22.491	-0.052	0.027	...	...
F569W	V	(V-I)	22.166	22.181	22.184	22.160	0.089	-0.003	...	2.0
F569W	V	(V-I)	22.498	22.513	22.516	22.492	-0.125	0.022	2.0	...
F606W	V	(B-V)	22.848	22.862	22.865	22.842	0.293	0.015	...	1.7
F606W	V	(B-V)	23.638	23.652	23.655	23.632	-0.284	0.081	1.7	...
F606W	V	(V-I)	22.848	22.862	22.865	22.842	0.254	0.012	...	2.0
F606W	V	(V-I)	23.638	23.652	23.655	23.632	-0.247	0.065	2.0	...
F622W	R	(V-R)	22.327	22.341	22.340	22.324	-0.252	-0.111	...	...
F675W	R	(U-R)	22.040	22.054	22.053	22.037	0.039	-0.007	...	...
F675W	R	(B-R)	22.021	22.035	22.034	22.018	0.092	-0.017	...	...
F675W	R	(V-R)	22.020	22.034	22.033	22.017	0.253	-0.125	...	...
F675W	R	(R-I)	22.011	22.025	22.024	22.008	0.273	-0.066	...	...
F702W	R	(V-R)	22.424	22.439	22.438	22.422	0.343	-0.177	...	0.6
F702W	R	(V-R)	22.302	22.317	22.316	22.300	0.486	-0.079	0.6	...
F785LP	I	(V-I)	20.630	20.665	20.668	20.637	0.091	0.020	...	...
F791W	I	(V-I)	21.432	21.467	21.469	21.438	-0.029	-0.004	...	1.0
F791W	I	(V-I)	21.473	21.508	21.510	21.479	-0.084	0.011	1.0	...
F814W	I	(U-I)	21.560	21.595	21.597	21.566	-0.018	0.002	...	...
F814W	I	(B-I)	21.580	21.615	21.617	21.586	-0.031	0.007	...	...
F814W	I	(V-I)	21.584	21.619	21.621	21.590	-0.062	0.025	...	...
F814W	I	(R-I)	21.584	21.619	21.621	21.590	-0.112	0.084	...	...
F850LP	I	(V-I)	19.872	19.907	19.909	19.879	0.160	0.023	...	...
F1042M	I	(V-I)	16.059	16.094	16.096	16.065	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) 20.250 20.273 20.254 20.276 -0.581 0.777 ... 0.5

F380W B (B-V) 20.602 20.625 20.606 20.628 -0.943 0.103 0.5 ...

F410M B (B-V) 18.895 18.918 18.899 18.920 -0.183 -0.287 ... ...

F439W B (U-B) 20.086 20.109 20.090 20.111 -0.103 -0.046 ... ...

F439W B (B-V) 20.099 20.122 20.103 20.124 0.003 -0.088 ... ...

F439W B (B-R) 20.093 20.116 20.097 20.118 0.019 -0.049 ... ...

F439W B (B-I) 20.096 20.119 20.100 20.121 0.005 -0.023 ... ...

F450W B (B-V) 21.197 21.220 21.201 21.223 0.230 -0.003 ... ...

F467M B (B-V) 19.128 19.151 19.132 19.154 0.480 -0.299 ... 0.5

F467M B (B-V) 19.079 19.102 19.083 19.105 0.432 -0.002 0.5 ...

F547M V (B-V) 20.851 20.851 20.857 20.870 0.031 -0.039 ... 1.0

F547M V (B-V) 20.803 20.803 20.809 20.822 0.056 -0.016 1.0 ...

F547M V (V-I) 20.851 20.851 20.857 20.870 0.027 -0.032 ... 1.1

F547M V (V-I) 20.803 20.803 20.809 20.822 0.049 -0.013 1.1 ...

F555W V (U-V) 21.727 21.728 21.734 21.746 -0.014 0.005 ... ...

F555W V (B-V) 21.746 21.747 21.753 21.765 -0.060 0.033 ... ...

F555W V (V-R) 21.751 21.752 21.758 21.770 -0.121 0.120 ... ...

F555W V (V-I) 21.746 21.747 21.753 21.765 -0.052 0.027 ... ...

F569W V (V-I) 21.416 21.416 21.422 21.435 0.089 -0.003 ... 2.0

F569W V (V-I) 21.748 21.748 21.754 21.767 -0.125 0.022 2.0 ...

F606W V (B-V) 22.097 22.097 22.104 22.116 0.293 0.015 ... 1.7

F606W V (B-V) 22.887 22.887 22.894 22.906 -0.284 0.081 1.7 ...

F606W V (V-I) 22.097 22.097 22.104 22.116 0.254 0.012 ... 2.0

F606W V (V-I) 22.887 22.887 22.894 22.906 -0.247 0.065 2.0 ...

F622W R (V-R) 21.562 21.583 21.578 21.579 -0.252 -0.111 ... ...

F675W R (U-R) 21.275 21.296 21.291 21.293 0.039 -0.007 ... ...

F675W R (B-R) 21.256 21.277 21.272 21.274 0.092 -0.017 ... ...

F675W R (V-R) 21.255 21.276 21.271 21.273 0.253 -0.125 ... ...

F675W R (R-I) 21.246 21.267 21.262 21.264 0.273 -0.066 ... ...

F702W R (V-R) 21.659 21.681 21.675 21.677 0.343 -0.177 ... 0.6

F702W R (V-R) 21.537 21.559 21.553 21.555 0.486 -0.079 0.6 ...

F785LP I (V-I) 19.893 19.908 19.901 19.905 0.091 0.020 ... ...

F791W I (V-I) 20.694 20.709 20.703 20.706 -0.029 -0.004 ... 1.0

F791W I (V-I) 20.735 20.750 20.744 20.747 -0.084 0.011 1.0 ...

F814W I (U-I) 20.822 20.837 20.831 20.834 -0.018 0.002 ... ...

F814W I (B-I) 20.842 20.857 20.851 20.854 -0.031 0.007 ... ...

F814W I (V-I) 20.846 20.861 20.855 20.858 -0.062 0.025 ... ...

F814W I (R-I) 20.846 20.861 20.855 20.858 -0.112 0.084 ... ...

F850LP I (V-I) 19.135 19.149 19.143 19.146 0.160 0.023 ... ...

F1042M I (V-I) 15.321 15.336 15.330 15.333 0.350 0.022 ... ...

Filter	SMAG	SCOL	ZP(PC1)	ZP(WFC2)	ZP(WFC3)	ZP(WFC4)	T1	T2	Cmin	Cmax
F380W	B	(B-V)	20.250	20.273	20.254	20.276	-0.581	0.777	...	0.5
F380W	B	(B-V)	20.602	20.625	20.606	20.628	-0.943	0.103	0.5	...
F410M	B	(B-V)	18.895	18.918	18.899	18.920	-0.183	-0.287	...	...
F439W	B	(U-B)	20.086	20.109	20.090	20.111	-0.103	-0.046	...	...
F439W	B	(B-V)	20.099	20.122	20.103	20.124	0.003	-0.088	...	...
F439W	B	(B-R)	20.093	20.116	20.097	20.118	0.019	-0.049	...	...
F439W	B	(B-I)	20.096	20.119	20.100	20.121	0.005	-0.023	...	...
F450W	B	(B-V)	21.197	21.220	21.201	21.223	0.230	-0.003	...	...
F467M	B	(B-V)	19.128	19.151	19.132	19.154	0.480	-0.299	...	0.5
F467M	B	(B-V)	19.079	19.102	19.083	19.105	0.432	-0.002	0.5	...
F547M	V	(B-V)	20.851	20.851	20.857	20.870	0.031	-0.039	...	1.0
F547M	V	(B-V)	20.803	20.803	20.809	20.822	0.056	-0.016	1.0	...
F547M	V	(V-I)	20.851	20.851	20.857	20.870	0.027	-0.032	...	1.1
F547M	V	(V-I)	20.803	20.803	20.809	20.822	0.049	-0.013	1.1	...
F555W	V	(U-V)	21.727	21.728	21.734	21.746	-0.014	0.005	...	...
F555W	V	(B-V)	21.746	21.747	21.753	21.765	-0.060	0.033	...	...
F555W	V	(V-R)	21.751	21.752	21.758	21.770	-0.121	0.120	...	...
F555W	V	(V-I)	21.746	21.747	21.753	21.765	-0.052	0.027	...	...
F569W	V	(V-I)	21.416	21.416	21.422	21.435	0.089	-0.003	...	2.0
F569W	V	(V-I)	21.748	21.748	21.754	21.767	-0.125	0.022	2.0	...
F606W	V	(B-V)	22.097	22.097	22.104	22.116	0.293	0.015	...	1.7
F606W	V	(B-V)	22.887	22.887	22.894	22.906	-0.284	0.081	1.7	...
F606W	V	(V-I)	22.097	22.097	22.104	22.116	0.254	0.012	...	2.0
F606W	V	(V-I)	22.887	22.887	22.894	22.906	-0.247	0.065	2.0	...
F622W	R	(V-R)	21.562	21.583	21.578	21.579	-0.252	-0.111	...	...
F675W	R	(U-R)	21.275	21.296	21.291	21.293	0.039	-0.007	...	...
F675W	R	(B-R)	21.256	21.277	21.272	21.274	0.092	-0.017	...	...
F675W	R	(V-R)	21.255	21.276	21.271	21.273	0.253	-0.125	...	...
F675W	R	(R-I)	21.246	21.267	21.262	21.264	0.273	-0.066	...	...
F702W	R	(V-R)	21.659	21.681	21.675	21.677	0.343	-0.177	...	0.6
F702W	R	(V-R)	21.537	21.559	21.553	21.555	0.486	-0.079	0.6	...
F785LP	I	(V-I)	19.893	19.908	19.901	19.905	0.091	0.020	...	...
F791W	I	(V-I)	20.694	20.709	20.703	20.706	-0.029	-0.004	...	1.0
F791W	I	(V-I)	20.735	20.750	20.744	20.747	-0.084	0.011	1.0	...
F814W	I	(U-I)	20.822	20.837	20.831	20.834	-0.018	0.002	...	...
F814W	I	(B-I)	20.842	20.857	20.851	20.854	-0.031	0.007	...	...
F814W	I	(V-I)	20.846	20.861	20.855	20.858	-0.062	0.025	...	...
F814W	I	(R-I)	20.846	20.861	20.855	20.858	-0.112	0.084	...	...
F850LP	I	(V-I)	19.135	19.149	19.143	19.146	0.160	0.023	...	...
F1042M	I	(V-I)	15.321	15.336	15.330	15.333	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