Space Telescope Science Institute   5.6.1 CCD Pixel Response Function  5.6.3 Encircled Energy

5.6.2 Model PSFs


Table 5.9 and Table 5.10 give ACS model PSFs in the central 5 ×5 pixel region in two wavelength bands (filters). Numbers listed are the fraction of the total energy received in each pixel. The models have been generated using Tiny TIM, taking into account the HST optical aberrations and obscurations as well as the CCD pixel response function. Field dependent geometrical distortions are included. The real PSF will also differ from the model because of the jitter in the HST pointing, HST focus variation (focus breathing), and other instrumental effects, some of which are briefly discussed below. The SBC PSF is shown Figure 5.10.


Table 5.9: Model ACS CCD PSFs.
WFC model PSF, filter F435W


WFC model PSF, filter F814W
0.00
0.01
0.01
0.01
0.00

0.01
0.01
0.02
0.01
0.01
0.01
0.04
0.07
0.05
0.02

0.01
0.03
0.07
0.03
0.02
0.02
0.08
0.17
0.08
0.02

0.02
0.07
0.18
0.07
0.02
0.01
0.04
0.08
0.04
0.01

0.01
0.03
0.07
0.03
0.01
0.00
0.01
0.02
0.01
0.00

0.01
0.02
0.02
0.01
0.00
HRC model PSF, filter F435W


HRC model PSF, filter F814W
0.01
0.01
0.01
0.01
0.01

0.00
0.01
0.02
0.01
0.00
0.02
0.03
0.06
0.03
0.01

0.01
0.04
0.05
0.04
0.01
0.01
0.06
0.16
0.06
0.01

0.02
0.05
0.08
0.05
0.02
0.01
0.03
0.07
0.03
0.01

0.01
0.04
0.05
0.04
0.01
0.01
0.02
0.01
0.01
0.01

0.00
0.01
0.02
0.01
0.00


Table 5.10: Model ACS SBC PSFs.
SBC PSF at 120 nm

SBC PSF at 160 nm
<0.01
0.01
0.01
0.01
<0.01

<0.01
<0.01
<0.01
<0.01
<0.01
0.01
0.02
0.03
0.02
0.01

<0.01
0.02
0.04
0.02
<0.01
0.01
0.03
0.15
0.03
0.01

<0.01
0.04
0.20
0.04
<0.01
0.01
0.02
0.03
0.02
0.01

<0.01
0.02
0.04
0.02
<0.01
<0.01
0.01
0.01
0.01
<0.01

<0.01
<0.01
<0.01
<0.01
<0.01


 5.6.1 CCD Pixel Response Function  5.6.3 Encircled Energy
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