WavecorrStep

class jwst.wavecorr.wavecorr_step.WavecorrStep(name=None, parent=None, config_file=None, _validate_kwds=True, **kws)[source]

Bases: JwstStep

Apply wavelength offsets to off-center NIRSpec point sources.

Create a Step instance.

Parameters:

namestr: The name of the Step instance. Used in logging messages and in cache filenames. If not provided, one will be generated based on the class name.
parentStep: The parent step of this step. Used to determine a fully-qualified name for this step, and to determine the mode in which to run this step.
config_filestr or pathlib.Path: The path to the config file that this step was initialized with. Use to determine relative path names of other config files.
_validate_kwdsbool: Validate given kws against specs/config.
**kwsdict: Additional parameters to set. These will be set as member variables on the new Step instance.

Attributes Summary

`class_alias`
`reference_file_types`
`spec`

Methods Summary

process(step_input)

Apply the wavelength correction to the input data.

Attributes Documentation

class_alias = 'wavecorr'

reference_file_types: ClassVar = ['wavecorr']

spec

Methods Documentation

process(step_input)[source]

Apply the wavelength correction to the input data.

Wavelength corrections are applied only to point sources in NIRSpec MOS and FS data.

The algorithm uses a reference file which is a look-up table of wavelength correction as a function of slit’s x-position and wavelength. The x-direction is the one parallel to dispersion/wavelength for both MOS and FS slits.

The slit’s x-position is read from the source_xpos attribute in the input slit metadata. For MOS data, the x-position is read from the msa_metadata_file in the assign_wcs step. For FS data, the x-position is calculated from the dither x_offset value in the extract_2d step.

The wavelength value used to look up the wavelength correction at each dispersion element is an average of the wavelength values in the cross-dispersion direction at that element.

Parameters:

step_inputstr, MultiSlitModel, or SlitModel: Input file name or datamodel to correct.

Returns:

output_modelMultiSlitModel or SlitModel: The corrected datamodel.