[Comm2011] FF - gain

[Konrad Kuijken]

> 
> 
> - when comparing similar exposures with different electronic filter 
> settings in fact 31 out of 32 chips show signal changes corresponding to 
> gain change deduced from the "gain recipe". So it seems gain recipe 
> works well, and there is indeed a different effective gain for different 
> filter settings.
> 


Hi Edwin,
THe fact that the gain recipe gives different results for different filter settings does NOT necessarily mean the gain changed. The recipe assumed that the filter does not have any smoothing effect but this may be wrong. So photometric tests of the gain are very important. 
Can we do this test quickly?
Koen





> All this will be further investigated coming days.
> 
> its amazing we can already do all those things!!
> 
> When involving astrometry, which we can , we can even have a look at 
> gain changes over the fov and  and make fisrt guess of illumination 
> correction. Will be done coming days.
> 
> Edwin
> 
> -- 
> -------------------------------------------------------------------------
> Prof. Dr. Edwin A. Valentijn       University of Groningen
> Coordinator Target                 www   : www.rug.nl/target
> Head OmegaCEN                      www   : www.astro.rug.nl/omegacen
> Kapteyn Astronomical Institute     tel   : +31 (0)50 3634011/4036 (secr)
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> NL-9700 AV Groningen               e-mail: valentyn at astro.rug.nl
> The Netherlands                    www   : www.astro.rug.nl/~valentyn
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