# Verification Datasets Meeting 2016-04-06 Minutes **URL:** \ **Category:** Data Management\ **Tags:** verificationdataset\ **Created:** [April 6, 2016, 6:04pm UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661 "2016-04-06T18:04:39Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![nidever](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/nidever/32/29_2.png) [@nidever](https://www.rubin.community/u/nidever)\ **Post date:** [April 6, 2016, 6:04pm UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661/1 "2016-04-06T18:04:39Z")
Verification Datasets meeting: Attendees: Simon, Colin, David, Frossie, Hsin-Fang **Simon:** - astrometric offsets between the different bands, not much headway - template quality coadds for differencing, defaults don’t work, not-PSF-matched - Kaiser coadds, adding in likelihood space, similar to “optimal coadd” method, paper came out recently - no movement on MOPS at the moment - Jess Ford, gave talk on new MOPS method, looking at clustering of points phased onto a test orbit would have to do billions of test orbits, but might be feasible **Colin:** - no update - Link to Kaiser coadd paper (unpublished) [http://spider.ipac.caltech.edu/staff/fmasci/home/astro\_refs/PanStars\_Coadder.pdf](http://spider.ipac.caltech.edu/staff/fmasci/home/astro_refs/PanStars_Coadder.pdf) **Hsin-Fang:** - nothing to update **Angelo:** - QA database, queries to select samples - SQR-008 tech note - ideas for improving the current baseline schema - schema reflects what’s in the DPDD - need way of selecting point sources, in coadds have better method, but need one at single-frame-level at least to compute the image quality to see if it’s good enough to go on to coadd processing - Simon mentioned that there will be QA metrics from Level 1 that could be used in Level 2, these QA metrics are not well defined and not clear if they will be persisted - Colin mentioned that there will be lots of quanities that will be measured and could be persisted but are not specified in DPDD, this would be a good exercise to flesh out what we want to save **David:** - COSMOS re-reduction with SDSS as reference [https://confluence.lsstcorp.org/display/SQRE/COSMOS+DECam+data+reduction](https://confluence.lsstcorp.org/display/SQRE/COSMOS+DECam+data+reduction) - still trying to figure out why the photometric scatter is larger than expected - more failures were because there was no reference data at that position in the sky, i.e. no SDSS coverage for the southern standard star fields - for calexps where there were reference data 99.8% succeeded in proccessCcdDecam - Angelo suggested using pixel quality flags to select good sources - Simon, photcalib spits out RMS per chip, at bright end, compare to scatter from multiple measurements - are the chip-to-chip fluxmag0 variations constant over time, would explain ~7% variations in fluxmag0 variations in z-band, but low scatter from bright stars from multiple measurements ---
**Author:** ![price](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/price/32/488_2.png) [@price](https://www.rubin.community/u/price)\ **Post date:** [April 6, 2016, 7:39pm UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661/2 "2016-04-06T19:39:56Z")
> [@nidever](#): > > the photometric scatter is larger than expected SDSS is not very good in Cosmos. I offered previously to run your DECam data against the PS1 catalog and provide you a DECam-based calibrated catalog, but I was crazy busy at the time. If you make the necessary science frames and calibs available for me to download, I might be able to do it now. ---
**Author:** ![nidever](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/nidever/32/29_2.png) [@nidever](https://www.rubin.community/u/nidever)\ **Post date:** [April 6, 2016, 8:19pm UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661/3 "2016-04-06T20:19:37Z")
That would be great. All of the data are on lsst-dev:/lsst8/decam/redux/cp/cosmos/. ---
**Author:** ![price](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/price/32/488_2.png) [@price](https://www.rubin.community/u/price)\ **Post date:** [April 7, 2016, 12:18am UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661/4 "2016-04-07T00:18:21Z")
What visits should I use? ---
**Author:** ![price](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/price/32/488_2.png) [@price](https://www.rubin.community/u/price)\ **Post date:** [April 7, 2016, 12:20am UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661/5 "2016-04-07T00:20:19Z")
Even better, what command-lines should I use? ---
**Author:** ![nidever](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/nidever/32/29_2.png) [@nidever](https://www.rubin.community/u/nidever)\ **Post date:** [April 7, 2016, 3:16pm UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661/6 "2016-04-07T15:16:32Z")
Here are the four groups of visits (the rest are of standard star fields, most at low DEC): 176837-176854 177071-177122 177337-177367 177726-177756 These are the config overrides that I use, but note that I haven’t updated to the new processCcd yet. config.calibrate.doPhotoCal=True config.calibrate.doAstrometry=True config.calibrate.measurePsf.starSelector.name="secondMoment" config.doWriteCalibrate=True config.doDeblend=True ---
**Author:** ![price](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/price/32/488_2.png) [@price](https://www.rubin.community/u/price)\ **Post date:** [April 7, 2016, 3:32pm UTC](https://www.rubin.community/t/verification-datasets-meeting-2016-04-06-minutes/661/7 "2016-04-07T15:32:13Z")
There’s no need to reduce the entire dataset to construct a reference catalog. Please choose a subset of visits that will cover the area in each filter. You should use the `objectSize` star selector instead of `secondMoment`.