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. A tutorial on the steps of running fgcmcal are found in the cookbook.

This fgcmcal task runs on sourceTable_visit catalogs from visits constrained by the --id parameter on the command line.

At the current time, fgcmcal does not support Gen3.

This is the second task in a typical fgcmcal processing chain. The first is FgcmMakeLutTask, the third is FgcmFitCycleTask, and the fourth is FgcmOutputProductsTask.

FgcmBuildStarsTableTask is available as a command-line task, fgcmBuildStarsTable.py.

Processing summary

FgcmBuildStarsTableTask runs this sequence of operations:

1. Finds unique visits and collates visit metadata, including exposure time, pointing, typical psf size, background level.

2. Reads in all sources, selecting good stars according to the chosen source selector.

3. Matches sources internally across bands to get a unique multi-band list of possible calibration stars.

4. Matches possible calibration stars to a reference catalog.

5. All results are stored in the output repo fgcm-process directory.

fgcmBuildStarsTable.py command-line interface

fgcmBuildStarsTable.py REPOPATH [@file [@file2 ...]] [--output OUTPUTREPO | --rerun RERUN] [--id] [other options]

Key arguments:

REPOPATH

The input Butler repository’s URI or file path.

Key options:

--id:

The data IDs to process.

See also

See Command-line task argument reference for details and additional options.

Python API summary

from lsst.fgcmcal.fgcmBuildStarsTable import FgcmBuildStarsTableTask

classFgcmBuildStarsTableTask(butler=None, 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...

methodrunDataRef(butler, dataRefs)

Cross-match and make star list for FGCM Input...

See also

See the FgcmBuildStarsTableTask API reference for complete details.

Butler datasets

When run as the fgcmBuildStarsTable.py command-line task, or directly through the runDataRef method, FgcmBuildStarsTableTask obtains datasets from the input Butler data repository and persists outputs to the output Butler data repository. Note that configurations for FgcmBuildStarsTableTask, and its subtasks, affect what datasets are persisted and what their content is.

Input datasets

sourceTable_visit

Full-depth source catalog, per-visit, in parquet format

calexp (s)

Calibrated exposures produced by ProcessCcdTask (for exposure metadata)

fgcmLookupTable

FGCM look-up table produced by FgcmMakeLutTask

Output datasets

fgcmVisitCatalog

Catalog (lsst.afw.table) of visit metadata

fgcmStarObservations

Catalog of star observations

fgcmStarIds

Catalog of unique star ids, positions, and number of observations

fgcmStarIndices

Catalog of indices linking unique star ids to star observations

fgcmReferenceStars

Catalog of reference stars matched to unique star ids.

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

'objectSize'

lsst.meas.algorithms.objectSizeStarSelector.ObjectSizeStarSelectorTask

'flagged'

lsst.meas.algorithms.flaggedSourceSelector.FlaggedSourceSelectorTask

'astrometry'

lsst.meas.algorithms.astrometrySourceSelector.AstrometrySourceSelectorTask

'matcher'

lsst.meas.algorithms.matcherSourceSelector.MatcherSourceSelectorTask

'diaCatalog'

lsst.ip.diffim.diaCatalogSourceSelector.DiaCatalogSourceSelectorTask

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

ccdDataRefName

Default

'ccd'

Field type

str Field

dataRef name for the ‘ccd’ field, usually ‘ccd’ or ‘detector’.

coarseNside

Default

8

Field type

int Field

Healpix coarse Nside for partitioning matches

connections

Data type

lsst.pipe.base.config.Connections

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.

filterMap

Default

{}

Field type

DictField

Key type

str

Value type

str

Mapping from ‘filterName’ to band. Deprecated: This field is no longer used, and has been deprecated by DM-28088. It will be removed after v22. Use physicalFilterMap instead.

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

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

saveMetadata

Default

True

Field type

bool Field

Flag to enable/disable metadata saving for a task, enabled by default.

visitDataRefName

Default

'visit'

Field type

str Field

dataRef name for the ‘visit’ field, usually ‘visit’.

Examples

See the cookbook for worked examples.