Snell

class stdatamodels.jwst.transforms.Snell(angle, kcoef, lcoef, tcoef, tref, pref, temperature, pressure, name=None)

Bases: Model

Apply transforms, including Snell’s law, through the NIRSpec prism.

Initialize the model of the NIRSpec prism.

Parameters:

anglefloat

Prism angle in deg.

kcoeflist

K coefficients in Sellmeier equation.

lcoeflist

L coefficients in Sellmeier equation.

tcoeflist

Thermal coefficients of glass.

treffloat

Reference temperature in K.

preffloat

Reference pressure in ATM.

temperaturefloat

System temperature during observation in K

pressurefloat

System pressure during observation in ATM.

namestr, optional

Name of the model

Attributes Summary

n_inputs
n_outputs
standard_broadcasting

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.
compute_refraction_index(lam, temp, tref, ...)	Calculate and return the refraction index.
evaluate(lam, alpha_in, beta_in, zin)	Go through the prism, evaluating refraction and reflection of each surface.

Attributes Documentation

n_inputs = 4

n_outputs = 3

standard_broadcasting = False

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.

static compute_refraction_index(lam, temp, tref, pref, pressure, kcoef, lcoef, tcoef)

Calculate and return the refraction index.

Use the simpler SellmeierGlass equation if the temperature difference is small (<20K), otherwise use the more complex SellmeierZemax equation.

Parameters:

lamfloat or np.ndarray

Wavelength in meters.

tempfloat

System temperature during observation in K.

treffloat

Reference temperature in K.

preffloat

Reference pressure in ATM.

pressurefloat

System pressure during observation in ATM.

kcoeflist

K coefficients in Sellmeier equation.

lcoeflist

L coefficients in Sellmeier equation.

tcoeflist

Thermal coefficients of glass.

Returns:

nfloat

Refraction index.

evaluate(lam, alpha_in, beta_in, zin)

Go through the prism, evaluating refraction and reflection of each surface.

Parameters:

lamfloat or np.ndarray

Wavelength in meters.

alpha_in, beta_infloat or np.ndarray

Incident angles.

zinfloat or np.ndarray

Incoming z coordinate. Not used for the calculation.

Returns:

xout, yout, zoutfloat

Outgoing x, y, z coordinates.