FgcmOutputProductsTask¶

FgcmOutputProductsTask uses the output from FgcmFitCycleTask to generate a full suite of output products (photometric calibration files, fgcm_photoCalib; atmosphere transmissions, transmission_atmosphere_fgcm; and standard star calibrated reference catalogs ref_cat) for use in downstream processing.

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

FgcmOutputProductsTask is available as a command-line task, fgcmOutputProducts.py.

Processing summary¶

FgcmOutputProductsTask reads in outputs from FgcmFitCycleTask, with the cycleNumber specified in the config file, translates these tables to formats used by coaddition and other downstream processing.

fgcmOutputProducts.py command-line interface¶

Note that no --id arguments are used by fgcmOutputProducts.py.

fgcmOutputProducts.py REPOPATH [@file [@file2 ...]] [--output OUTPUTREPO | --rerun RERUN] [--config cycleNumber=finalCycleNumber] [other options]

Key arguments:

REPOPATH: The input Butler repository’s URI or file path.

Key options:

--config cycleNumber=finalCycleNumer:: The cycleNumber used for the isFinalCycle run of FgcmFitCycleTask

Python API summary¶

from lsst.fgcmcal.fgcmOutputProducts import FgcmOutputProductsTask

classFgcmOutputProductsTask(butler=None, **kwargs): Output products from FGCM global calibration...

attributeconfig: Access configuration fields and retargetable subtasks.

methodrun(dataRefDict, physicalFilterMap, returnCatalogs=True, butler=None): Run the output products task...

methodrunDataRef(butler): Make FGCM output products for use in the stack...

Butler datasets¶

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

Input datasets¶

fgcmStandardStars: Catalog of standard stars from fit.
fgcmZeropoints: Catalog of zero-point information.
fgcmAtmosphereParameters: Catalog of atmosphere parameters.
fgcmBuildStars_config or fgcmBuildStarsTable_config: Configuration of task used to build stars for the fgcmcal run. Only one should be available depending on the specific task used.
fgcmFitCycle_config: Configuration of FgcmFitCycleTask used for the final fit cycle.

Output datasets¶

fgcm_stars: Reference catalog of standard stars.
fgcm_photoCalib: One fgcm_photoCalib photometric calibration file is output for each visit / ccd.
transmission_atmosphere_fgcm: One atmospheric transmission curve is output for each visit.

The reference catalog (fgcm_stars) is an lsst.afw.table.SimpleCatalog that can be used as a reference catalog, including band_flux and band_fluxErr measurements per band (in nJy), as well as additional information including band_nGood (the number of photometric observations per band), band_nTotal (the total number of observations per band), and band_nPsfCandidate (the number of observations per band that were flagged as PSF candidates).

Retargetable subtasks¶

photoCal¶

Default: lsst.pipe.tasks.photoCal.PhotoCalTask
Field type: ConfigurableField

task to perform ‘absolute’ calibration

refObjLoader¶

Default: lsst.meas.algorithms.loadIndexedReferenceObjects.LoadIndexedReferenceObjectsTask
Field type: ConfigurableField

reference object loader for ‘absolute’ photometric calibration

Configuration fields¶

connections¶

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

Configurations describing the connections of the PipelineTask to datatypes

cycleNumber¶

Default: None
Field type: int Field

Final fit cycle from FGCM fit

datasetConfig¶

Data type: lsst.meas.algorithms.ingestIndexReferenceTask.DatasetConfig
Field type: ConfigField

Configuration for writing/reading ingested catalog

doApplyMeanChromaticCorrection¶

Default: True
Field type: bool Field

Apply the mean chromatic correction to the zeropoints?

doAtmosphereOutput¶

Default: True
Field type: bool Field

Output atmospheres in transmission_atmosphere_fgcm format

doComposeWcsJacobian¶

Default: True
Field type: bool Field

Compose Jacobian of WCS with fgcm calibration for output photoCalib?

doRefcatOutput¶

Default: True
Field type: bool Field

Output standard stars in reference catalog format

doReferenceCalibration¶

Default: False
Field type: bool Field

Transfer ‘absolute’ calibration from reference catalog? This afterburner step is unnecessary if reference stars were used in the full fit in FgcmFitCycleTask.

doZeropointOutput¶

Default: True
Field type: bool Field

Output zeropoints in fgcm_photoCalib format

physicalFilterMap¶

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

Mapping from ‘physicalFilter’ to band.

referenceMinMatch¶

Default: 50
Field type: int Field

Minimum number of stars matched to reference catalog to be used in statistics

referencePixelizationMinStars¶

Default: 200
Field type: int Field

Minimum number of stars per healpix pixel to select for comparisonto the specified reference catalog

referencePixelizationNPixels¶

Default: 100
Field type: int Field

Number of healpix pixels to sample to do comparison. Doing too many will take a long time and not yield any more precise results because the final number is the median offset (per band) from the set of pixels.

referencePixelizationNside¶

Default: 64
Field type: int Field

Healpix nside to pixelize catalog to compare to reference catalog

saveMetadata¶

Default: True
Field type: bool Field

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

Examples¶

See the cookbook for worked examples.

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