FgcmMakeLutTask¶

FgcmMakeLutTask computes a look-up table tracking atmosphere and instrumental variations for use in the fgcmcal fits. The intention is that this is run once for a given observatory/instrument and should only be updated when instrumental parameters change (e.g., updated filter and ccd throughput curves), or in the extremely rare case if an observatory is relocated to a different elevation or latitude.

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

FgcmMakeLutTask is available as a command-line task, fgcmMakeLut.py.

Processing summary¶

FgcmMakeLutTask uses an input atmosphere table (preferable) or a list of atmosphere parameters, combined with the instrumental throughput as a function of position, to compute a look-up table used in the fgcmcal fits.

fgcmMakeLut.py command-line interface¶

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

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

Key arguments:

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

Python API summary¶

from lsst.fgcmcal.fgcmMakeLut import FgcmMakeLutTask

classFgcmMakeLutTask(butler=None, initInputs=None, **kwargs): Make Look-Up Table for FGCM...

attributeconfig: Access configuration fields and retargetable subtasks.

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

methodrunDataRef(butler): Make a Look-Up Table for FGCM...

Butler datasets¶

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

Input datasets¶

camera: Camera geometry and detector object
transmission_optics: Optics transmission curve for the instrument
transmission_filter: Filter transmission curve (as a function of position) for the instrument

Output datasets¶

fgcmLookUpTable: FGCM atmosphere and instrument look-up table

Retargetable subtasks¶

No subtasks.

Configuration fields¶

atmosphereTableName¶

Default: None
Field type: str Field (optional)

FGCM name or filename of precomputed atmospheres

connections¶

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

Configurations describing the connections of the PipelineTask to datatypes

parameters¶

Data type: lsst.fgcmcal.fgcmMakeLut.FgcmMakeLutParametersConfig
Field type: ConfigField

Atmosphere parameters (required if no atmosphereTableName)

physicalFilters¶

Default: []
Field type: str ListField

List of physicalFilter labels to generate look-up table.

saveLogOutput¶

Default: True
Field type: bool Field

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

saveMetadata¶

Default: True
Field type: bool Field

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

stdPhysicalFilterOverrideMap¶

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

Override mapping from physical filter labels to ‘standard’ physical filter labels. The ‘standard’ physical filter defines the transmission curve that the FGCM standard bandpass will be based on. Any filter not listed here will be mapped to itself (e.g. g->g or HSC-G->HSC-G). Use this override for cross-filter calibration such as HSC-R->HSC-R2 and HSC-I->HSC-I2.

Examples¶

See the cookbook for worked examples.

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