FgcmBuildFromIsolatedStarsTask#
FgcmBuildFromIsolatedStarsTask ingests the isolated star catalogs generated by lsst.pipe.tasks.isolatedStarAssociation.IsolatedStarAssociationTask over all the tracts to create a global input catalog of associated stars for input to fgcm.
This task (optionally) additionally associates these stars with a reference catalog stars which may be used for overall absolute calibration or as an additional constraint on the fit.
This is the second task in a typical fgcmcal processing chain.
The first is FgcmMakeLutTask, the third is FgcmFitCycleTask, and the fourth is FgcmOutputProductsTask.
Processing summary#
FgcmBuildFromIsolatedStarsTask runs this sequence of operations:
Finds visits and collates visit metadata, including exposure time, pointing, typical psf size, background level.
Reads in all isolated stars and associated source observations to create a multi-band list of possible calibration stars.
Finds high density regions to down-sample calibration stars.
Flags reserved stars in a repeatable way.
Matches possible calibration stars to a reference catalog.