Sky2Pix_ZenithalPerspective

class astropy.modeling.projections.Sky2Pix_ZenithalPerspective(*args, **kwargs)

Bases: Sky2PixProjection, Zenithal

Zenithal perspective projection - sky to pixel.

Corresponds to the AZP projection in FITS WCS.

\[\begin{split}x &= R \sin \phi \\ y &= -R \sec \gamma \cos \theta\end{split}\]

where:

\[R = \frac{180^{\circ}}{\pi} \frac{(\mu + 1) \cos \theta} {(\mu + \sin \theta) + \cos \theta \cos \phi \tan \gamma}\]

Parameters:

mufloat

Distance from point of projection to center of sphere in spherical radii, μ. Default is 0.

gammafloat

Look angle γ in degrees. Default is 0°.

Attributes Summary

gamma
mu
param_names	Names of the parameters that describe models of this type.

Attributes Documentation

gamma = _ParameterDS('gamma', value=0.0)

mu = _ParameterDS('mu', value=0.0)

param_names = ('mu', 'gamma')

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 Parameter attributes defined in the class body.