[Comm2011] FF - gain

[Edwin A. Valentyn]

this is what I decsribed in the mail: a photometric check of the gain 
giving results consistent with the "gain recipe"!
Research is further on-going- but indeed this is an important observation
Edwin

On 14-4-2011 9:22, Konrad Kuijken wrote:
>
>>
>>
>> - 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 
>> <http://www.rug.nl/target>
>> Head OmegaCEN                      www   : www.astro.rug.nl/omegacen 
>> <http://www.astro.rug.nl/omegacen>
>> Kapteyn Astronomical Institute     tel   : +31 (0)50 3634011/4036 (secr)
>> P.O.Box 800                        mobile: +31 (0)6 48276416
>> NL-9700 AV Groningen               e-mail: valentyn at astro.rug.nl 
>> <mailto:valentyn at astro.rug.nl>
>> The Netherlands                    www   : www.astro.rug.nl/~valentyn 
>> <http://www.astro.rug.nl/%7Evalentyn>
>> -------------------------------------------------------------------------
>>
>>
>>
>>
>>
>>
>>
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-- 
-------------------------------------------------------------------------
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)
P.O.Box 800                        mobile: +31 (0)6 48276416
NL-9700 AV Groningen               e-mail: valentyn at astro.rug.nl
The Netherlands                    www   : www.astro.rug.nl/~valentyn
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