# FilterDefinition¶

class lsst.obs.base.FilterDefinition(physical_filter: str, lambdaEff: float, band: str = None, doc: str = None, afw_name: str = None, lambdaMin: float = nan, lambdaMax: float = nan, alias: set = frozenset())

Bases: object

The definition of an instrument’s filter bandpass.

This class is used to interface between the Filter class and the Gen2 CameraMapper and Gen3 Instruments and physical_filter/band Dimension.

This class is likely temporary, until we have a better versioned filter definition system that includes complete transmission information.

Attributes Summary

 afw_name If not None, the name of the Filter object. alias Alternate names for this filter. band The generic name of a filter not associated with a particular instrument (e.g. doc A short description of this filter, possibly with a link to more information. lambdaMax The maximum wavelength of this filter (nm; defined as 1% throughput) lambdaMin The minimum wavelength of this filter (nm; defined as 1% throughput)

Methods Summary

 defineFilter() Declare the filters via afw.image.Filter. makeFilterLabel() Create a complete FilterLabel for this filter.

Attributes Documentation

afw_name = None

If not None, the name of the Filter object.

This is distinct from physical_filter and band to maintain backwards compatibility in some obs packages. For example, for HSC there are two distinct r and i filters, named r/r2 and i/i2.

alias = frozenset()

Alternate names for this filter. These are added to the Filter alias list.

band = None

The generic name of a filter not associated with a particular instrument (e.g. r for the SDSS Gunn r-band, which could be on SDSS, LSST, or HSC).

Not all filters have an abstract filter: engineering or test filters may not have a genericly-termed filter name.

If specified and if afw_name is None, this is used as the Filter name field, otherwise it is added to the list of Filter aliases.

doc = None

lambdaMax = nan

The maximum wavelength of this filter (nm; defined as 1% throughput)

lambdaMin = nan

The minimum wavelength of this filter (nm; defined as 1% throughput)

Methods Documentation

defineFilter()

Declare the filters via afw.image.Filter.

makeFilterLabel()

Create a complete FilterLabel for this filter.