| Telescope | MDM 1.3m |
| Date | 4/6/1996 |
| Instrument | Charlotte |
| Filter | B_mdm |
| Exposure Time |
600 s |
| Other | processed |
Problem:The bright and dark features in the lower right hand corner of the image are due to a misalignment of the filter wheel. The filter did not stop at the exact same position for every image. During the flats, the filter wheel vignetted part of the image, while during the target images, it apparently blocked a different portion of the CCD. Therefore, in this processed image, you find a light deficient feature (filter wheel blocking the target image) and a bright feature (overcorrection during processing using vignetted flatfields). |
Fix:The filter wheel would somehow have to be fixed. The best idea might be to contact the telescope support staff for help. Since the vignetting will most likely only occur in the outer regions of the images, the center part of the images will be usable, provided there is no dust on the filters which would move around from one image to the next as well. |
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