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this is what I decsribed in the mail: a photometric check of the
gain giving results consistent with the "gain recipe"!<br>
Research is further on-going- but indeed this is an important
observation<br>
Edwin<br>
<br>
On 14-4-2011 9:22, Konrad Kuijken wrote:
<blockquote
cite="mid:13D76DBA-9589-48EB-9389-F72DD7BB8E17@strw.leidenuniv.nl"
type="cite">
<div><br>
</div>
<blockquote type="cite">
<div><font class="Apple-style-span" color="#000000"><br>
</font><span></span><br>
<span>- when comparing similar exposures with different
electronic filter </span><br>
<span>settings in fact 31 out of 32 chips show signal changes
corresponding to </span><br>
<span>gain change deduced from the "gain recipe". So it seems
gain recipe </span><br>
<span>works well, and there is indeed a different effective
gain for different </span><br>
<span>filter settings.</span><br>
<span></span><br>
</div>
</blockquote>
<div><br>
</div>
<div><br>
</div>
<div>Hi Edwin,</div>
<div>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. </div>
<div>Can we do this test quickly?</div>
<div>Koen</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<br>
<blockquote type="cite">
<div><span>All this will be further investigated coming days.</span><br>
<span></span><br>
<span>its amazing we can already do all those things!!</span><br>
<span></span><br>
<span>When involving astrometry, which we can , we can even
have a look at </span><br>
<span>gain changes over the fov and and make fisrt guess of
illumination </span><br>
<span>correction. Will be done coming days.</span><br>
<span></span><br>
<span>Edwin</span><br>
<span></span><br>
<span>-- </span><br>
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3634011/4036 (secr)</span><br>
<span>P.O.Box 800 mobile: +31 (0)6
48276416</span><br>
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</blockquote>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
-------------------------------------------------------------------------
Prof. Dr. Edwin A. Valentijn University of Groningen
Coordinator Target www : <a class="moz-txt-link-abbreviated" href="http://www.rug.nl/target">www.rug.nl/target</a>
Head OmegaCEN www : <a class="moz-txt-link-abbreviated" href="http://www.astro.rug.nl/omegacen">www.astro.rug.nl/omegacen</a>
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: <a class="moz-txt-link-abbreviated" href="mailto:valentyn@astro.rug.nl">valentyn@astro.rug.nl</a>
The Netherlands www : <a class="moz-txt-link-abbreviated" href="http://www.astro.rug.nl/~valentyn">www.astro.rug.nl/~valentyn</a>
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