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.

See also

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

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...

See also

See the FgcmMakeLutTask API reference for complete details.

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

filterNames

Default
None
Field type
str ListField
Filter names to build LUT (‘short’ names)

parameters

Data type
lsst.fgcmcal.fgcmMakeLut.FgcmMakeLutParametersConfig
Field type
ConfigField
Atmosphere parameters (required if no atmosphereTableName)

saveMetadata

Default
True
Field type
bool Field
Flag to enable/disable metadata saving for a task, enabled by default.

stdFilterNames

Default
None
Field type
str ListField
Standard filterNames (‘short’ names). Each filter in filterName will be calibrated to a matched stdFilterName. In regular usage, one has g->g, r->r, … In the case of HSC, one would have g->g, r->r2, r2->r2, … which allows replacement (or time-variable) filters to be properly cross-calibrated.

Examples

See the cookbook for worked examples.