<html><body bgcolor="#FFFFFF"><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><span>-------------------------------------------------------------------------</span><br><span>Prof. Dr. Edwin A. Valentijn University of Groningen</span><br><span>Coordinator Target www : <a href="http://www.rug.nl/target"><a href="http://www.rug.nl/target">www.rug.nl/target</a></a></span><br><span>Head OmegaCEN www : <a href="http://www.astro.rug.nl/omegacen"><a href="http://www.astro.rug.nl/omegacen">www.astro.rug.nl/omegacen</a></a></span><br><span>Kapteyn Astronomical Institute tel : +31 (0)50 3634011/4036 (secr)</span><br><span>P.O.Box 800 mobile: +31 (0)6 48276416</span><br><span>NL-9700 AV Groningen e-mail: <a href="mailto:valentyn@astro.rug.nl"><a href="mailto:valentyn@astro.rug.nl">valentyn@astro.rug.nl</a></a></span><br><span>The Netherlands www : <a href="http://www.astro.rug.nl/~valentyn"><a href="http://www.astro.rug.nl/~valentyn">www.astro.rug.nl/~valentyn</a></a></span><br><span>-------------------------------------------------------------------------</span><br><span></span><br><span></span><br><span></span><br><span></span><br><span></span><br><span></span><br><span></span><br><span>_______________________________________________</span><br><span>Comm2011 mailing list</span><br><span><a href="mailto:Comm2011@astro-wise.org">Comm2011@astro-wise.org</a></span><br><span><a href="http://listman.astro-wise.org/mailman/listinfo/comm2011">http://listman.astro-wise.org/mailman/listinfo/comm2011</a></span><br><span></span><br></div></blockquote></body></html>