| Telescope | MDM 2.4m |
| Date | 11/3/1996 |
| Instrument | Templeton |
| Filter | V_MDM |
| Exposure Time |
10s per exposure |
| Other | Focus Exposure |
Problem:This focus exposure (multiple exposures of the chip with small offsets in between exposures) was taken during twilight. The vertical strips across the chip are most likely a saturation feature, perhaps a saturation of the CCD potential wells, but not the A/D converter (if the A/D converter reaches saturation, the image would be uniformly affected). The reason for the saturation is very likely the bright twilight sky. Some pixels seem to be more affected than others; stellar images are visible in the top left corner. |
Fix:The problem was "fixed" by just taking another focus sequence after twilight (with darker sky background). One could also reduce the exposure time. |