[Aavso-photometry] cosmic rays - some progress

[Michael Newberry]

[...]

> SBIG sell their Kodak chip cameras just with a permanent CCD cover
> slip glas. Their argument is that any dust thats located on the cover slip
> glas would show up in the light and flat frames just as grey 'donuts'
> (instead of as black 'rocks', due to the increased distance from the
> chip) that should flat-field out pretty well. But FLI leaves this choice
> to
> their customer:
> http://www.fli-cam.com/FLIsupport/coverslip.htm
> http://www.fli-cam.com/FLIsupport/camera_windows.htm
>
> Clear skies
>  Wolfgang

Hi Wolfgang,

I have heard this same cover skip argument  countless times from some
particular camera vendors and chip makers. But it is really lame. Dust will
not settle on either the cover glass or the chip if the chip is mounted in a
clean environment and the chamber is sealed---which is how it should be done
for a product costing... how many dollars ???.

Michael Newberry