WFPC2 Technical Instrument Report 97-08:
SMOV Flat Field Check
-Biretta and Wiggs
We compare WFPC2 Earthflats taken before and after the 1997 Servicing Mission. Most of the field-of-view shows no change (<<1%) in flat field calibration. The largest changes and occur within a few pixels of the CCD corners and reach ~1.5%; these are likely attributable to long-term changes in the camera/OTA geometry, rather than SM97.