The Internal CCD Flat Fields
Abstract
The internal flat field lamp has been used since launch to monitor the stability of the ACS HRC and WFC flat fields. The only ubiquitous change observed in these flat fields is an excess of pixel responses that are low. This excess of values that are low by more than 3σ varies from factors of two to several over what is expected from the tail of the Gaussian distribution of Poisson statistics. Occasionally, a pattern resembling the growth rings of a tree are seen on the WFC with an amplitude of ~1%; but this anomaly is sufficiently rare and short lived, so that the monitoring frequency can be decreased.
- Publication:
-
Instrument Science Report ACS 2005-09
- Pub Date:
- July 2005
- Bibcode:
- 2005acs..rept....9B
- Keywords:
-
- Hubble Space Telescope;
- HST;
- Space Telescope Science Institute;
- Internal Flat Field