FgcmBuildStarsTableTask¶

FgcmBuildStarsTableTask finds all the single-visit sources in a repository (or a subset based on command-line parameters) from sourceTable_visit parquet tables and extracts all the potential photometric calibration stars for input into fgcm. This task additionally uses fgcm to match star observations into unique stars, and performs as much cleaning of the input catalog as possible.

This is the second task in a typical fgcmcal processing chain. The first is FgcmMakeLutTask, the third is FgcmFitCycleTask, and the fourth is FgcmOutputProductsTask. This task is still usable and tested, but the replacement FgcmBuildFromIsolatedStarsTask is preferred for modern pipelines.

Processing summary¶

FgcmBuildStarsTableTask runs this sequence of operations:

Finds unique visits and collates visit metadata, including exposure time, pointing, typical psf size, background level.
Reads in all sources, selecting good stars according to the chosen source selector.
Matches sources internally across bands to get a unique multi-band list of possible calibration stars.
Matches possible calibration stars to a reference catalog.
All results are stored in the output repo fgcm-process directory.

Python API summary¶

from lsst.fgcmcal.fgcmBuildStarsTable import FgcmBuildStarsTableTask

classFgcmBuildStarsTableTask(initInputs=None, **kwargs): Build stars for the FGCM global calibration, using sourceTable_visit catalogs...

attributeconfig: Access configuration fields and retargetable subtasks.

methodrun(**kwargs): Run task algorithm on in-memory data...

Retargetable subtasks¶

fgcmLoadReferenceCatalog¶

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

FGCM reference object loader

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.FgcmBuildStarsTableConfigConnections
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 CCD 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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