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-574 DRP 2-D Pipeline <p>Current FRD analysis has focused on extracting out signals when the PSF is in focus. While ideally no defocus is required to extract FRD effects, it is clear that at high defocus FRD variations are readily quantifiable. The fine defocus mirrors will safely allow for a +/- 100 micron variation in focus during analysis, so it is worth determining how much we can learn by defocusing out this much.</p> PIPE2D-574

Increasing defocus effect on FRD analysis

Story Normal Done Done Brent Belland Brent Belland Wed, 6 May 2020 18:43:16 +0000 Mon, 4 Jan 2021 20:22:55 +0000 Fri, 4 Sep 2020 22:35:13 +0000 0 1 <p><a href="https://pfspipe.ipmu.jp/jira/browse/PIPE2D-509" title="How much do we need to defocus in order to measure change of effective frd" class="issue-link" data-issue-key="PIPE2D-509">PIPE2D-509</a> involved determining how much of an FRD change was required to be detectable at given SNR. Further FRD work has been focused on how FRD effects the PSF and in-focus image, particularly focused on quantifying the effect on PSF rather than quantifying FRD variation. However, given that the fine defocus motor permits 100 um defocus, it would be valuable to revisit the defocus question with a emphasis on determining PSF variations due to FRD variations. The goals of these tickets are related though not the same.</p> <p>The maximum % variation in a full boxcar extraction was tested across 120 positions at three levels of defocus: In-focus (0 um defocus), intermediate defocus (32 um defocus), and 'maximum' fine defocus (100 um defocus). The results are shown in DefocusPositions.png, where in focus is shown in downward-pointing triangles, intermediate focus as circles, and maximum defocus as upward pointing triangles. The maximum percent variation does generally increase with higher defocus as to be expected, though specific positions across the detector can have different trends. The analysis may be impeded by the use of the maximum % variation metric rather than quantifying else wise, such as 1D boxcar extraction or SNR variations (see <a href="https://pfspipe.ipmu.jp/jira/browse/PIPE2D-601" title="Detectability of PSF change with FRD via SNR rather than percent variation" class="issue-link" data-issue-key="PIPE2D-601">PIPE2D-601</a>, <a href="https://pfspipe.ipmu.jp/jira/browse/PIPE2D-602" title="Determine better diagnostics for FRD variation" class="issue-link" data-issue-key="PIPE2D-602">PIPE2D-602</a>). Currently the magnitude of the effect is being examined more closely, since determining how much defocus would help PSF characterization would help prioritize calibrations for sky subtraction.</p> <p>Surprisingly little change in the 2D residuals was detected with defocuses up to the fine defocus motor limit, so future analysis has focused on in-focus data.</p> Relates PIPE2D-627 PIPE2D-509 Development Rank 0|02qps1:i Sprint 2DDRP-2021 A