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.

Python API summary¶

from lsst.fgcmcal.fgcmBuildFromIsolatedStars import FgcmBuildFromIsolatedStarsTask

classFgcmBuildFromIsolatedStarsTask(initInputs=None, **kwargs): Build star catalog for FGCM global calibration, using the isolated star catalogs...

attributeconfig: Access configuration fields and retargetable subtasks.

methodrun(*, camera, visit_summary_handle_dict, isolated_star_cat_handle_dict, isolated_star_source_handle_dict, lookup_table_handle=None): Run the fgcmBuildFromIsolatedStarsTask...

Retargetable subtasks¶

fgcmLoadReferenceCatalog¶

Default: lsst.fgcmcal.fgcmLoadReferenceCatalog.FgcmLoadReferenceCatalogTask
Field type: ConfigurableField

FGCM reference object loader

reserve_selection¶

Default: lsst.pipe.tasks.reserveIsolatedStars.ReserveIsolatedStarsTask
Field type: ConfigurableField

Task to select reserved stars.

sourceSelector¶

Default

'science'

Field type

Single-selection RegistryField

Choices

'science': lsst.meas.algorithms.sourceSelector.ScienceSourceSelectorTask
'references': lsst.meas.algorithms.sourceSelector.ReferenceSourceSelectorTask
'null': lsst.meas.algorithms.sourceSelector.NullSourceSelectorTask
'objectSize': lsst.meas.algorithms.objectSizeStarSelector.ObjectSizeStarSelectorTask
'flagged': lsst.meas.algorithms.flaggedSourceSelector.FlaggedSourceSelectorTask
'astrometry': lsst.meas.algorithms.astrometrySourceSelector.AstrometrySourceSelectorTask
'matcher': lsst.meas.algorithms.matcherSourceSelector.MatcherSourceSelectorTask

How to select sources

Configuration fields¶

apertureInnerInstFluxField¶

Default: 'base_CircularApertureFlux_12_0_instFlux'
Field type: str Field

Full name of instFlux field that contains inner aperture flux for aperture correction proxy

apertureOuterInstFluxField¶

Default: 'base_CircularApertureFlux_17_0_instFlux'
Field type: str Field

Full name of instFlux field that contains outer aperture flux for aperture correction proxy

coarseNside¶

Default: 8
Field type: int Field

Healpix coarse Nside for partitioning matches

connections¶

Data type: lsst.pipe.base.config.FgcmBuildFromIsolatedStarsConfigConnections
Field type: ConfigField

Configurations describing the connections of the PipelineTask to datatypes

densityCutMaxPerPixel¶

Default: 1000
Field type: int Field

Density cut number of stars per pixel

densityCutNside¶

Default: 128
Field type: int Field

Density cut healpix nside

doApplyWcsJacobian¶

Default: True
Field type: bool Field

Apply the jacobian of the WCS to the star observations prior to fit?

doModelErrorsWithBackground¶

Default: True
Field type: bool Field

Model flux errors with background term?

doReferenceMatches¶

Default: True
Field type: bool Field

Match reference catalog as additional constraint on calibration

doSubtractLocalBackground¶

Default: False
Field type: bool Field

Subtract the local background before performing calibration? This is only supported for circular aperture calibration fluxes.

instFluxField¶

Default: 'slot_CalibFlux_instFlux'
Field type: str Field

Faull name of the source instFlux field to use, including ‘instFlux’. The associated flag will be implicitly included in badFlags

isolationRadius¶

Default: 2.0
Field type: float Field

Isolation radius (arcseconds)

localBackgroundFluxField¶

Default: 'base_LocalBackground_instFlux'
Field type: str Field

Full name of the local background instFlux field to use.

matchNside¶

Default: 4096
Field type: int Field

Healpix Nside for matching

matchRadius¶

Default: 1.0
Field type: float Field

Match radius (arcseconds)

minPerBand¶

Default: 2
Field type: int Field

Minimum observations per band

nVisitsPerCheckpoint¶

Default: 500
Field type: int Field

Number of visits read between checkpoints

physicalFilterMap¶

Default: {}
Field type: DictField
Key type: str
Value type: str

Mapping from ‘physicalFilter’ to band.

primaryBands¶

Default: None
Field type: str ListField

Bands for ‘primary’ star matches. A star must be observed in one of these bands to be considered as a calibration star.

psfCandidateName¶

Default: 'calib_psf_candidate'
Field type: str Field

Name of field with psf candidate flag for propagation

randomSeed¶

Default: None
Field type: int Field (optional)

Random seed for high density down-sampling.

referenceCCD¶

Default: 40
Field type: int Field

Reference detector for checking PSF and background.

requiredBands¶

Default: ()
Field type: str ListField

Bands required for each star

saveLogOutput¶

Default: True
Field type: bool Field

Flag to enable/disable saving of log output for a task, enabled by default.

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