https://pfspipe.ipmu.jp/jira This file is an XML representation of an issue en-us 8.3.4 803005 13-09-2019 https://pfspipe.ipmu.jp/jira/browse/PIPE2D-980 DRP 2-D Pipeline <p>Spectrographic camera has different levels of obscuration (detector+struts+slit) at different positions of the detector. The amount of flux which is obscured also depends on the illumination, i.e., on the position on the focal plane.</p> PIPE2D-980

Estimate camera obscuration on different locations of the detector

Task Normal Done Done ncaplar ncaplar Fri, 18 Feb 2022 15:13:24 +0000 Mon, 16 Oct 2023 20:01:16 +0000 Thu, 17 Mar 2022 18:31:26 +0000 0 3 <p>I have presented initial version of the result today at Princeton meting. These were just showing fraction of the obscuration as a function on the detector position and angle on the focal plane.The improvements which we agreed upon today:</p> <p>1. Create the solution showing obscuration of the pupil per fiber - because each fiber on the detector corresponds to one particular angle of the focal plane.<br/> 2. Create solution as a function of FRD </p> <p>The updated solution is given in Figure <img src="https://pfspipe.ipmu.jp/jira/images/icons/attach/noimage.png" imagetext="obscuration_as_fun_frd.png|thumbnail" align="absmiddle" border="0" /> It shows the obscuration fraction as a function of fiber_id and wavelength (i.,e., position on the detector). Left panel shows the result for nominal FRD (I believe JEG said it is 2.1 mrad? - I have to check), and the right hand side is for 0 mrad. The large scale structure is mostly a function of the angle of the focal plane where different fibers are positioned. Fibers which are in the center of the detector tend to be at the edge of the focal plane, so the effect is more pronounced. The fibers which are at the edge of the detector actually tend to be in the center of the focal plane. <br/> The FRD effect seems to be small. Previously we thought it might be much larger, but I now realize that I made an error when comparing the illumination pattern that JEG provided - the difference is actually very small. <br/> I reserve the right to check the results once again, before discussing it on Monday Princeton meeting, on March 7. </p> <p>It looks like 15 - 20% between the green (most the fibres) and the bad block at the right for nominal FRD. I assume that this is SM1, presumably the pattern will be different for the other spectrographs</p> <p>As Robert and I just discussed, the blue is actually the ``best'' block, nearest to the center of the focal plane (because blue is the lower amount of the obscuration). This is indeed for SM1, other spectrographs will be different. </p> <p>After some more considerations, I believe this is correct estimate of the camera obscuration:  <span class="image-wrap" style=""><a id="15129_thumb" href="https://pfspipe.ipmu.jp/jira/secure/attachment/15129/15129_angle_on_focal_plane_all_SM.png" title="angle_on_focal_plane_all_SM.png" file-preview-type="image" file-preview-id="15129" file-preview-title="angle_on_focal_plane_all_SM.png"><img src="https://pfspipe.ipmu.jp/jira/secure/thumbnail/15130/_thumb_15130.png" style="border: 0px solid black" /></a></span> . The mean obscuration is around 30%, with some variations due to FRD, wavelength, and (most importantly) position of the fiber on the focal plane. </p> <p>I expect that all SMs will look quite similar, because the distribution of fibers in focal plane is similar:  <span class="image-wrap" style=""><a id="15127_thumb" href="https://pfspipe.ipmu.jp/jira/secure/attachment/15127/15127_frd_differece.png" title="frd_differece.png" file-preview-type="image" file-preview-id="15127" file-preview-title="frd_differece.png"><img src="https://pfspipe.ipmu.jp/jira/secure/thumbnail/15129/_thumb_15129.png" style="border: 0px solid black" /></a></span> .</p> <p>The FRD makes only a small difference. The following plots shows the difference in obscuration due to FRD, and it is around 1% between 0 mrad and nominal 23 mrad:  <span class="image-wrap" style=""><a id="15127_thumb" href="https://pfspipe.ipmu.jp/jira/secure/attachment/15127/15127_frd_differece.png" title="frd_differece.png" file-preview-type="image" file-preview-id="15127" file-preview-title="frd_differece.png"><img src="https://pfspipe.ipmu.jp/jira/secure/thumbnail/15127/_thumb_15127.png" style="border: 0px solid black" /></a></span></p> <p>As discussed during telecon on Monday, March 14, the final step is to calculate mean obscuration, to supply it to <a href="https://pfspipe.ipmu.jp/jira/secure/ViewProfile.jspa?name=kiyoto.yabe" class="user-hover" rel="kiyoto.yabe">Kiyoto Yabe</a></p> <p><a href="https://pfspipe.ipmu.jp/jira/secure/ViewProfile.jspa?name=kiyoto.yabe" class="user-hover" rel="kiyoto.yabe">Kiyoto Yabe</a>  The mean obscuration for nominal FRD is calculated to be 30.5% (if FRD=0, mean obscuration is 31.5%). </p> Relates SURVEY-30 Development Rank 0|02qpq3:r3s00000000008y Sprint 2DDRP-2022 B Story Points 2.0