> ... And now
> that flats are (presumed) final, a focus on the defringing recipe is needed
> as well.
Forgot to comment on this ... As you know, I was trying in December
to come up with some better procedure for defringing. There is some
tentative evidence that fringing is improved when you defringe with
fringes of about the same amplitude in DU/s (after allowing for airmass
effects). This is maybe not surprising: night sky level is an excita-
tion effect, and excitation affects the relative strengths of lines
in the airglow.
However by far the biggest effect I found was that the really gross
defringing problems happen when the mosaic is not at the proper
temperature. This was quite striking.
I'm afraid I won't have a chance to work on this further for a
month or two.
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Chris Pritchet pritchet at uvic.ca
Dept of Physics & Astronomy
http://www.astro.uvic.ca/~pritchet
University of Victoria
P.O. Box 3055 250-721-7744 (office)
Victoria, BC V8W 3P6 250-884-5047 (cell)
CANADA 250-721-7715 (FAX)
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Received on Fri Feb 15 2008 - 14:01:55 HST