lsst.pipe.tasks.colorterms.Colorterm Class Reference

Colorterm correction for one pair of filters. More...

Inheritance diagram for lsst.pipe.tasks.colorterms.Colorterm:

Public Member Functions
def	getCorrectedMagnitudes (self, refCat, filterName)
def	transformSource (self, source)
	Transform the brightness of a source. More...
def	transformMags (self, primary, secondary)
	Transform brightness. More...
def	propagateFluxErrors (self, primaryFluxErr, secondaryFluxErr)

Static Public Attributes
	primary
	secondary
	c0
	c1
	c2

Detailed Description

Colorterm correction for one pair of filters.

The transformed magnitude p' is given by p' = primary + c0 + c1*(primary - secondary) + c2*(primary - secondary)**2

To construct a Colorterm, use keyword arguments: Colorterm(primary=primaryFilterName, secondary=secondaryFilterName, c0=c0value, c1=c1Coeff, c2=c2Coeff) where c0-c2 are optional. For example (omitting c2): Colorterm(primary="g", secondary="r", c0=-0.00816446, c1=-0.08366937)

This is subclass of Config. That is a bit of a hack to make it easy to store the data in an appropriate obs_* package as a config override file. In the long term some other means of persistence will be used, at which point the constructor can be simplified to not require keyword arguments. (Fixing DM-2831 will also allow making a custom constructor).

Definition at line 41 of file colorterms.py.

Member Function Documentation

getCorrectedMagnitudes()

def lsst.pipe.tasks.colorterms.Colorterm.getCorrectedMagnitudes	(		self,
			refCat,
			filterName
	)

Return the colorterm corrected magnitudes for a given filter.

Parameters
----------
refCat : `lsst.afw.table.SimpleCatalog`
    The reference catalog to apply color corrections to.
filterName : `str`
    The camera filter to correct the reference catalog into.

Returns
-------
RefMag : `np.ndarray`
    The corrected AB magnitudes.
RefMagErr : `np.ndarray`
    The corrected AB magnitude errors.

Raises
------
KeyError
    Raised if the reference catalog does not have a flux uncertainty
    for that filter.

Notes
-----
WARNING: I do not know that we can trust the propagation of magnitude
errors returned by this method. They need more thorough tests.

Definition at line 63 of file colorterms.py.

propagateFluxErrors()

def lsst.pipe.tasks.colorterms.Colorterm.propagateFluxErrors	(		self,
			primaryFluxErr,
			secondaryFluxErr
	)

Definition at line 137 of file colorterms.py.

transformMags()

def lsst.pipe.tasks.colorterms.Colorterm.transformMags	(		self,
			primary,
			secondary
	)

Transform brightness.

Parameters

[in]	primary	brightness in primary filter (magnitude)
[in]	secondary	brightness in secondary filter (magnitude)

Returns

the transformed brightness (as a magnitude)

Definition at line 127 of file colorterms.py.

transformSource()

def lsst.pipe.tasks.colorterms.Colorterm.transformSource	(		self,
			source
	)

Transform the brightness of a source.

Parameters

[in]

source

source whose brightness is to be converted; must support get(filterName) (e.g. source.get("r")) method, as do afw::table::Source and dicts.

Returns

the transformed source magnitude

Definition at line 118 of file colorterms.py.

Member Data Documentation

c0

lsst.pipe.tasks.colorterms.Colorterm.c0

static

Definition at line 59 of file colorterms.py.

c1

lsst.pipe.tasks.colorterms.Colorterm.c1

static

Definition at line 60 of file colorterms.py.

c2

lsst.pipe.tasks.colorterms.Colorterm.c2

static

Definition at line 61 of file colorterms.py.

primary

lsst.pipe.tasks.colorterms.Colorterm.primary

static

Definition at line 57 of file colorterms.py.

secondary

lsst.pipe.tasks.colorterms.Colorterm.secondary

static

Definition at line 58 of file colorterms.py.

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The documentation for this class was generated from the following file:

• python/lsst/pipe/tasks/colorterms.py