Posted to CCD-world:
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Has anyone any knowledge on how pixel-pixel QE varitions
changes as a function of
1) Wavelength
2) Time
I'm looking for quantitative real results, but theory guesses
are welcome !
These variations are traditionally removed (or at least attempts
are bravely made) by high-quality flat-fielding at the wavelength one is
observing at. But has anyone done any quantitaive tests of how dependent the
RATIO's of pix-pix variations are on wavelength ?
The idea behind this is that a set of super-flats could be
provided to observers for specific wavelength regions per CCD in
e.g. long-slit spectrographs. There are of course instrument
issues involved in this also, but some spectrographs would
lend themselves to this type of calibration if the
pix-pix response was not steeply dependent on wavelength.
e.g can a spectroscopic W flat in the region 4500-4700 be used
to remove pix-pix variations in the 5000-5200 region ?
Also, the pix-pix variations would need to be constant a
function of time. Has anyone any experience of this also ?
We are intending to do these experiments at ING, but any
advice or results that has already been done would be
very much appreciated. We will try this out with a 1k Tek
and an EEV42-80.
regards
steve
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Dr. Stephen J. Smartt ING Support Astronomer
email: sjst at ing.iac.es
Isaac Newton Group Tel (Mountain): +34 22 405655
Apartado de Correos 368 Tel (Sea-Level: +34 22 425439
Santa Cruz de La Palma, 38700 Fax (Mountain) : +34 22 405646
Canary Islands,Spain Fax (Sea Level) : +34 22 425401
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