CCD Window

["Thomas Droege" <tdroege2@earthlink.net>]

Reading the CCD-World list I realize that I have probably bought windows
without anti-reflection coatings.  A comment by a manufacturer on the list
says that if chips are ordered with glued on windows they get glass with
anti-reflection coatings, but if taped on windows are ordered they get
plain glass.  So there is a good chance that some or all my chips have
plain glass windows.

I am wondering if this could cause our noise floor?

If images are taken in the same position, then the reflections would be in
the same places.  So while they would add to the noise, they might be
consistent and would be calibrated out by the pipeline.  However, moving
around in position there would be no way to calibrate reflections.  What do
you all think?

I could easily remove the cover glass.  This at least removes two surfaces.
Now that the cameras are working pretty reliably, I would not mind removing
the covers.  However, one trades dust on the window which is out of focus
for dust on the surface of the CCD which covers specific pixels and
probably moves around a little.  Anyone had experience with this that can
make a recommendation as to the trade off?

Tom Droege


Tom  Droege Jennifer Malpass
tdroege2@earthlink.net