Project: datamanagement
Issue DM-1525: Investigate halos around stars
Andrew Becker reports on dm-users: {quote} We have been using the LSST stack to reduce CFHT data at UW, and have come across a potential bug in the DM software. I don't see how this could be something intrinsic to the data, instead it seems like it could be a bug in the software triggered by its application to new data. I have a how to reproduce at NCSA at /lsst/home/becker/CFHT. Follow commands in the SETUP file to get an up-to-date version of the stack (b449) and a modified version of ip_isr (a hack to avoid overscan correction) and a private branch of obs_cfht (u/krughoff/ossos_support). If you run the commands in SOURCE_ME it will run the processCcd on a single CCD, in 2 modes, yielding 2 output directories. The second call merely sets the bin sizes to be the same amongst all the various background subtractions, but is sufficient to trigger the bug. A basic script included in the directory differences the 2 output calexps (a straight -=) and ds9 is used to view the diff. If you pan to e.g. 1845,546 you'll see a feature like attached in the difference (out1 on the left, out2 in the middle, diff on the right). This can be seen in various other parts of the image, as irregular annuli around bright blended objects. It suggests to me that during measurement some substamp manipulations are leaking into the original image. But you can kind of see in the center image that the second run seems to trigger the issue. {quote} And then: {quote} So to summarize: export LSSTSW=~lsstsw source ~lsstsw/bin/setup.sh setup lsst_apps -t b449 setup -k -r /nfs/lsst/home/becker/LSST/DMS/obs_cfht setup -k -r /nfs/lsst/home/becker/LSST/DMS/ip_isr setup -k -r /nfs/lsst/home/becker/LSST/DMS/processFile cd /nfs/lsst/home/becker/CFHT will set up your environment. The following is sufficient to recreate the bug, and create postIsrCCD images for processFile: processCcd.py input/ --id visit=1612606 ccd=8 --output out1/ --config isr.doAssembleDetrends=False isr.fringeAfterFlat=False isr.fringe.pedestal=False isr.doBias=False isr.doFlat=False isr.doFringe=False isr.doWrite=True calibrate.doPhotoCal=False calibrate.doAstrometry=False doDeblend=True processCcd.py input/ --id visit=1612606 ccd=8 --output out2/ --config isr.doAssembleDetrends=False isr.fringeAfterFlat=False isr.fringe.pedestal=False isr.doBias=False isr.doFlat=False isr.doFringe=False isr.doWrite=True calibrate.doPhotoCal=False calibrate.doAstrometry=False doDeblend=True detection.background.binSize=512 calibrate.detection.background.binSize=512 calibrate.background.binSize=512 Following are the calls I made to processFile.py (using my modified version of the processFile.git package), and which return images whose difference is exactly 0. So I don't really get whats happening with processFile, but it doesn't seem to be accepting my command-line config changes. processFile.py out1/postISRCCD/13AP06/E+0+0/2013-03-11/r/postISRCCD-1612606-08.fits --outputCalexp calexp1.fits -c calibrate.doPhotoCal=False calibrate.doAstrometry=False doDeblend=True calibrate.repair.doCosmicRay=False processFile.py out2/postISRCCD/13AP06/E+0+0/2013-03-11/r/postISRCCD-1612606-08.fits --outputCalexp calexp2.fits -c calibrate.doPhotoCal=False calibrate.doAstrometry=False doDeblend=True calibrate.repair.doCosmicRay=False detection.background.binSize=512 calibrate.detection.background.binSize=512 calibrate.background.binSize=512 processFile.py out2/postISRCCD/13AP06/E+0+0/2013-03-11/r/postISRCCD-1612606-08.fits --outputCalexp calexp3.fits -c calibrate.doPhotoCal=False calibrate.doAstrometry=False doDeblend=True calibrate.repair.doCosmicRay=False detection.background.binSize=1024 calibrate.detection.background.binSize=1024 calibrate.background.binSize=1024 {quote}
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