ACS Filters and Dispersers

The following tables show the three cameras’ ‘filters’ properties. The definitions of the columns below are those of the stsdas.synphot BANDPAR task. These definitions are summarized here. For further details please see the on-line help on BANDPAR. Here ‘INT’ refers to an integral over wavelength, and ‘THRU’ is the throughput of the filter at that wavelength. ‘LAM’ is wavelength.

Central Wavelength = bandpar.pivwv
   defined as PIVWV = SQRT(INT(THRU * LAM) / INT (THRU / LAM))
Mean Wavelength = bandpar.avgwv
   defined as AVGWV = INT(THRU * LAM) / INT(THRU)
Peak Wavelength = bandpar.wpeak
   defined as wavelength at peak throughput (WPEAK)
FWHM = bandpar.fwhm
   defined as FWHM = SQRT(8 * LOG(2)) * BANDW
Max Transmission = maximum transmission OF THE FILTER ONLY
   (no other optical components) as measured pre-launch in the lab
Max Throughput = bandpar.tpeak
   defined as peak bandpass throughput

The Range column describes the total range in wavelength where the filter throughput (by itself, no other optical components) is larger than 0.05%. For low-pass filters, the range is open-ended; the table lists in this case the range as the maximum range listed in the SYNPHOT/pysynphot throughput reference files.

The rightmost column, Fraction, is the fraction of light falling on the central pixel, assuming the point source PSF is centered on that pixel as estimated by Tiny Tim PSF simulations (3-gyro mode).

All data in these tables (except for the PSF-related ‘Fraction’) are generated from the STScI CDBS tables, which are updated as more accurate information is obtained. The observer is strongly advised to regenerate these tables from the most up-to-date data in CDBS if the exact values are critical to planning observations. The SYNPHOT user’s guide (Bushouse, 1998) is the best guide on how to do this.

HRC Filters

Filter Central Mean Peak FWHM Range Trans Thru Fraction
F475W 4775.7 4794.0 5000.2 986.23 1800 0.913701 0.24735 0.17
F502N 5022.9 5023.0 5005.5 85.867 145 0.7135654 0.19196 0.169
F550M 5579.9 5582.4 5550.3 389.02 740 0.8770255 0.24687 0.153
F555W 5356.0 5368.0 5059.8 841.13 1720 0.885 0.24037 0.159
F606W 5888.0 5926.1 6689.8 1565.5 2570 0.9517956 0.27447 0.143
F625W 6295.5 6309.2 6479.9 977.51 1720 0.915 0.26496 0.134
F658N 6583.8 6584.0 6592.0 136.27 180 0.9118735 0.26505 0.128
F775W 7665.1 7677.5 7320.1 1017.4 1910 0.947 0.23605 0.107
F850LP 9145.2 9161.6 8859.5 1269.1 >3080 0.976 0.13813 0.086
F892N 8916.1 8916.4 8915.4 237.98 320 0.9182586 0.13461 0.091
F220W 2255.4 2264.4 2219.9 441.03 1350 0.361 0.050401 0.175
F250W 2715.9 2727.4 2520.1 563.76 1980 0.48071 0.061124 0.166
F330W 3362.7 3367.2 3460.3 409.16 790 0.751 0.10714 0.156
F344N 3433.7 3433.8 3430.2 64.922 95 0.67994 0.10093 0.156
F435W 4311.0 4322.0 4760.1 728.95 8780 0.92799 0.22602 0.17
F660N 6599.1 6599.3 6595.4 175.72 100 0.7178267 0.20719 0.128
F814W 8115.3 8146.9 7459.5 1656.6 2870 0.991 0.23965 0.099
POL_UV 6231.7 6607.0 7399.7 4943.9 >18000 1.0 0.088816 0.135
POL_V 6943.2 7184.0 9206.6 4134.8 >16500 1.0 0.086172 0.121
PR200L 5650.2 6051.9 6460.4 4830.5 >9392 0.93 0.26908 0.151
CORON 5472.0 5926.3 6460.4 4926.1 0.475 0.13743 0.156
G800L 7506.4 7594.9 7000.0 2614.3 >6000 0.902 0.22724 0.110

SBC Filters

Filter Central Mean Peak FWHM Range Trans Thru Fraction
F115LP 1406.1 1415.0 1260.2 354.53 >8850 0.92705 0.057976 0.101
F122M 1273.7 1277.5 1216.0 213.97 1170 0.143 0.0095276 0.078
F125LP 1437.5 1445.2 1320.0 334.09 >8780 0.91 0.0529 0.108
F140LP 1527.0 1532.6 1390.1 294.08 >8650 0.89 0.04167 0.125
F150LP 1610.7 1614.7 1490.0 258.52 >8600 0.86812 0.029992 0.141
F165LP 1757.9 1760.1 1700.1 203.2 >8500 0.85 0.0090218 0.162
PR110L 1429.4 1438.1 1320.1 355.49 >8800 0.89444 0.045411 0.106
PR130L 1438.7 1446.6 1299.9 336.48 >8780 0.89611 0.053365 0.108

WFC Filters

Filter Central Mean Peak FWHM Range Trans Thru Fraction
F475W 4744.4 4763.0 4999.6 989.27 1800 0.913701 0.3736 0.213
F502N 5023.0 5023.1 5005.5 68.042 145 0.7135654 0.28985 0.210
F550M 5581.2 5583.5 5550.4 384.47 740 0.8770255 0.38211 0.216
F555W 5359.6 5371.8 5499.8 847.79 1720 0.885 0.37093 0.214
F606W 5917.7 5956.3 6689.8 1583.2 2570 0.9517956 0.46516 0.219
F625W 6310.5 6324.1 6479.9 978.32 1720 0.915 0.44337 0.22
F658N 6584.0 6584.4 6591.6 87.487 180 0.9118735 0.44498 0.22
F775W 7693.0 7705.4 7380.3 1023.4 1910 0.947 0.42868 0.206
F850LP 9054.8 9071.6 8610.3 1270.3 >3080 0.976 0.24829 0.147
F892N 8914.9 8915.1 8914.9 171.78 320 0.9182586 0.21473 0.154
F435W 4317.4 4327.3 4569.9 691.08 8780 0.92799 0.3807 0.217
F660N 6599.4 6599.5 6595.2 83.666 100 0.7178267 0.34844 0.0.22
F814W 8059.8 8087.4 7460.2 1541.6 2870 0.991 0.44092 0.197
POL_UV 6634.5 6874.9 7640.4 4053.7 >1800 1.0 0.16482 0.22
POL_V 6910.0 7134.4 7209.6 4017.0 >16500 1.0 0.1386 0.22
G800L 7480.7 7559.1 7199.8 2473.0 >6000 0.902 0.40081 0.210

Ramp Filters

Filter Central Range Camera
FR388N 3710-4050 2% WFC/HRC
FR423N 4050-4420 2% WFC
FR462N 4420-4820 2% WFC
FR656N 6270-6850 2% WFC/HRC
FR716N 6850-7470 2% WFC
FR782N 7470-8160 2% WFC
FR914M 7570-10710 9% WFC/HRC
FR853N 8160-8910 2% WFC
FR931N 8910-9720 2% WFC
FR459M 3810-5370 9% WFC/HRC
FR647M 5370-7570 9% WFC
FR1016N 9720-10610 2% WFC
FR505N 4820-5270 2% WFC/HRC
FR551N 5270-5750 2% WFC
FR601N 5750-6270 2% WFC

Please refer to Bohlin and Tsvetanov ( ISR ACS 00-05 ) for details about calculation of peak transmission for ramp filters.

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