Suspected Problem:

The scattered light visible all over the image is most likely due to a light leak in the filter wheel. When the filters were put into the filter wheel, the outside was not covered with black tape, thus allowing extraneous light to hit the CCD.

The stellar reflections (rings around the brighter stars in the image) are probably due to internal reflections in the filter. This can occur when the filter is inserted upside down, but should not happen when the filter is inserted correctly..

Fix: