The latest RC2 run was run with w_2020_50 (
DM-28140). This is the first time we are running with the gaia_dr2_20200414 reference catalog for the external astrometric calibration in jointcal, so some small differences in the astrometry would be expected. However, the differences are not small. To start, the stellar locus is now of order 33 mmag, whereas in the v21_0_0_rc1 run it was at 13 mmag. An "issue" is clearly visible in the stellar locus plots:
Also striking are the patterns seen in a match to the reference match catalog, e.g.:
Note that the plotting scripts are still loading in the ps1_pv3_3pi_20170110 to do the matching (to be updated on a forthcoming ticket), but initial investigations confirm that this cannot explain the amplitude & shape of these patterns.
This ticket is to look into any possible cause of these issues.