WavelengthFromGratingEquation

class stdatamodels.jwst.transforms.WavelengthFromGratingEquation(groove_density, order, **kwargs)

Bases: Model

Solve the 3D Grating Dispersion Law for the wavelength.

Initialize the model.

Parameters:

groove_densityint

Grating ruling density.

orderint

Spectral order.

**kwargs

Additional keyword arguments to pass to Model base class.

Attributes Summary

groove_density	Grating ruling density.
n_inputs
n_outputs
order	Spectral order.
param_names	Names of the parameters that describe models of this type.

Methods Summary

__call__(*inputs[, model_set_axis, ...])	Evaluate this model using the given input(s) and the parameter values that were specified when the model was instantiated.
evaluate(alpha_in, beta_in, alpha_out, ...)	Solve the 3D Grating Dispersion Law for the wavelength.

Attributes Documentation

groove_density = Parameter('groove_density', value=nan)

Grating ruling density.

n_inputs = 3

n_outputs = 1

order = Parameter('order', value=1.0)

Spectral order.

param_names = ('groove_density', 'order')

Names of the parameters that describe models of this type.

The parameters in this tuple are in the same order they should be passed in when initializing a model of a specific type. Some types of models, such as polynomial models, have a different number of parameters depending on some other property of the model, such as the degree.

When defining a custom model class the value of this attribute is automatically set by the ~astropy.modeling.Parameter attributes defined in the class body.

Methods Documentation

__call__(*inputs, model_set_axis=None, with_bounding_box=False, fill_value=nan, equivalencies=None, inputs_map=None, **new_inputs)

Evaluate this model using the given input(s) and the parameter values that were specified when the model was instantiated.

evaluate(alpha_in, beta_in, alpha_out, groove_density, order)

Solve the 3D Grating Dispersion Law for the wavelength.

Parameters:

alpha_infloat

The incident angle.

beta_infloat

Not used; see Notes.

alpha_outfloat

The refracted angle.

groove_densityfloat

The grating ruling density.

orderint

The spectral order.

Returns:

float

The wavelength

Notes

beta_in is not used in this equation but is here because it’s needed for the prism computation. Currently these two computations need to have the same interface.