This document describes the procedure for validating the first non-beta release of the jointcal package as a replacement for meas_mosaic.  Longer term requirements for jointcal are described in a separate document (draft here).  Because meas_mosaic only runs on Hyper Suprime-Cam data, the scientific performance tests here are also focused on HSC data.  The jointcal beta already supports additional cameras and we expect it to continue to do so, but as there's nothing to replace for other cameras there are no short-term requirements for its performance on them.

Basic Requirements

Science Quality Tests

As of  and , the validate_drp package can now (optionally) utilize the wcs and photoCalib datasets to calibrate the src dataset prior to computing its astrometric and photometric accuracy metrics.  To replace meas_mosaic, we require jointcal to match (no significant difference in metric value) or improve upon the following metrics as computed with meas_mosaic on HSC data.

No significant difference is a bit tricky to define here because most of these metrics are not accompanied by uncertainty estimates; to estimate them we'll use the RMS of the meas_mosaic metric (henceforth σ) results over different tracts of HSC Wide.  Differences less than 0.1 mmag for photometry or 0.1 mas for astrometry (even if larger than the cross-tract RMS, though I doubt the RMS across tracts will be that small) can also be ignored.

We will run the metric comparison independently on each of at least 19 tracts of HSC-SSP Wide data, as well as the (single tract) HSC-SSP UDeep COSMOS dataset.  No more than 1 of these 20 tracts shall have a regression from the meas_mosaic performance in that tract by more than 2σ, and none may deviate by more than 3σ.  The number of tracts may be extended if initial failure to achieve these rates appears to be due to statistical fluctuations.

The WCS mappings and photometric scalings output by meas_mosaic and jointcal should also be manually inspected for at least 5 visits in each of 5 tracts (including COSMOS) to look for unusual differences.

Doing the Work

Scheduling work is obviously a T/CAM responsibility, but it may be best to try to share the generation of the input data repositories for these tests with re-run of the full HSC-SSP PDR1 (NCSA may have already scheduled some time for this later this cycle).

Scientific validation of the results is the responsibility of the Pipeline Scientist.