WF/PC INSTRUMENT SCIENCE REPORT 90-01:
Bias Change During TV6
By Christine E. Ritchie and Shawn Ewald
October, 1989
Abstract excerpted from the report:
Analysis of WFPC images taken during JPL thermal vacuum tests has always shown a low level (~0.5 DN) difference of bias level between the odd and the even numbered columns. During TV6 (February - March, 1988) this pattern changed from even columns having the higher bias level to the odd columns being higher. The change occurred steadily over the duration of the TV6 and does not show a correlation with UV Flooding or decontamination (bake-out) activity. The mean bias level of the odd and even columns together shows a steady increase of about two DN per day over the twenty-five days of the TV6 test.
The complete report (PDF 0.23 MB) is available.