But the level is low enough such that it will be totally dominated by the sky background noise in broad band filters applications. Anyway, this does not extend over more than 200 pixels. The extra signal will be totally dominated by the sky background noise in broad band filters applications. But it has to be a concern with narrow band filters. Some softwares may complain about about such particularity.
Cosmetic is excellent.
The camera was aligned along the West-East axis by taking drift exposures. Then the locking screws were set tight on the side of the bonnette. This is no more an issue for the CFH12K data quality. The focal plane has been pushed back a bit into the dewar while a spacer between the cryostat and the mechanical stack has been removed, resulting in a 200 microns offset of the focal plane towards the filter. This is a good situation where most filters focus in the middle range of the bonnette.