SkyObjectsTask

class lsst.meas.algorithms.SkyObjectsTask(schema=None, **kwargs)

Bases: Task

Generate a list of Footprints of sky sources/objects (regions on the sky that do not otherwise have detections).

Parameters

schemalsst.afw.table.Schema

Schema used to create the output SourceCatalog, updated with fields that will be written by this task.

Methods Summary

run(mask, seed[, catalog])

Generate a list of Footprints of sky sources/objects.

Methods Documentation

run(mask, seed, catalog=None)

Generate a list of Footprints of sky sources/objects.

Sky objects don’t overlap with other objects. This is determined through the provided mask (in which objects are typically flagged as DETECTED).

Sky objects are positioned using a quasi-random Halton sequence number generator. This is a deterministic sequence that mimics a random trial and error approach whilst acting to minimize clustering of points for a given field of view. Up to nTrialSources points are generated, returning the first nSources that do not overlap with the mask.

Parameters

masklsst.afw.image.Mask

Input mask plane, which identifies pixels to avoid for the sky objects.

seedint

Random number generator seed.

cataloglsst.afw.table.SourceCatalog, optional

Catalog to add detected footprints to; modified in-place if any sky source/object footprints are created.

Returns

skyFootprintslist of lsst.afw.detection.Footprint

Footprints of sky objects. Each will have a peak at the center of the sky object.