| Telescope | MDM 1.3m |
| Date | 11/20/97 |
| Instrument | Echelle CCD |
| Filter | V |
| Exposure Time |
400 sec |
| Other | Dark exposure |
Problem:The temperature to which the CCD was to be cooled was set incorrectly in computer software and rather than being cooled to -100C it was only cooled to about -75C. After being unable to flatten or zero subtract out the strange structure, a long dark exposure was taken and revealed the missing structure which had to be subtracted out. |
Fix:Make sure the CCD is appropriately cooled or take dark exposures to subtract out the dark current. |
0 sec Zero frame with different structure
15 sec Twilight flat with different structure
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