BrightStarStamp

class lsst.meas.algorithms.BrightStarStamp(stamp_im: lsst.afw.image.maskedImage.MaskedImageF, gaiaGMag: float, gaiaId: int, position: lsst.geom.Point2I, archive_element: Optional[lsst.afw.table.io.Persistable] = None, annularFlux: Optional[float] = None)

Bases: lsst.meas.algorithms.stamps.AbstractStamp

Single stamp centered on a bright star, normalized by its annularFlux.

Parameters:

stamp_im : lsst.afw.image.MaskedImage

Pixel data for this postage stamp

position : lsst.geom.Point2I

Origin of the stamps in its origin exposure (pixels)

gaiaGMag : float

Gaia G magnitude for the object in this stamp

gaiaId : int

Gaia object identifier

annularFlux : Optional[float]

Flux in an annulus around the object

Attributes Summary

annularFlux
archive_element

Methods Summary

factory(stamp_im, metadata, idx[, …])	This method is needed to service the FITS reader.
measureAndNormalize(annulus[, statsControl, …])	Compute “annularFlux”, the integrated flux within an annulus around an object’s center, and normalize it.

Attributes Documentation

annularFlux = None

archive_element = None

Methods Documentation

classmethod factory(stamp_im, metadata, idx, archive_element=None)

This method is needed to service the FITS reader. We need a standard interface to construct objects like this. Parameters needed to construct this object are passed in via a metadata dictionary and then passed to the constructor of this class. This particular factory method requires keys: G_MAGS, GAIA_IDS, and ANNULAR_FLUXES. They should each point to lists of values.

Parameters:

stamp_im : lsst.afw.image.MaskedImage

Pixel data to pass to the constructor

metadata : dict

Dictionary containing the information needed by the constructor.

idx : int

Index into the lists in metadata

archive_element : lsst.afwTable.io.Persistable, optional

Archive element (e.g. Transform or WCS) associated with this stamp.

Returns:

brightstarstamp : BrightStarStamp

An instance of this class

measureAndNormalize(annulus, statsControl=<lsst.afw.math.StatisticsControl object>, statsFlag=<Property.MEAN: 4>, badMaskPlanes=('BAD', 'SAT', 'NO_DATA'))

Compute “annularFlux”, the integrated flux within an annulus around an object’s center, and normalize it.

Since the center of bright stars are saturated and/or heavily affected by ghosts, we measure their flux in an annulus with a large enough inner radius to avoid the most severe ghosts and contain enough non-saturated pixels.

Parameters:

annulus : lsst.afw.geom.spanSet.SpanSet

SpanSet containing the annulus to use for normalization.

statsControl : lsst.afw.math.statistics.StatisticsControl, optional

StatisticsControl to be used when computing flux over all pixels within the annulus.

statsFlag : lsst.afw.math.statistics.Property, optional

statsFlag to be passed on to afwMath.makeStatistics to compute annularFlux. Defaults to a simple MEAN.

badMaskPlanes : collections.abc.Collection [str]

Collection of mask planes to ignore when computing annularFlux.