There are a few characteristics of ACS that should be taken into account when imaging with ACS:
GAIN
setting for WFC primary observations is GAIN=2
. This allows for good sampling of the readout noise and allows one to reach the full well counts of WFC. For the HRC primary observations, the default gain is GAIN=2
. To sample the detector full well depth, GAIN=4 is needed, but this results in modest undersampling of the readout noise. For HRC ACQ
data, the default setting is GAIN=4
. Users may select the GAIN
they wish to use for their ACS observations by using the GAIN
optional parameter in their Phase II proposal. However, not all GAIN settings are supported (see Section 7.6).
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