Pix2Sky_CylindricalPerspective

class astropy.modeling.projections.Pix2Sky_CylindricalPerspective(*args, **kwargs)

Bases: Pix2SkyProjection, Cylindrical

Cylindrical perspective - pixel to sky.

Corresponds to the CYP projection in FITS WCS.

\[\begin{split}\phi &= \frac{x}{\lambda} \\ \theta &= \arg(1, \eta) + \sin{-1}\left(\frac{\eta \mu}{\sqrt{\eta^2 + 1}}\right)\end{split}\]

where:

\[\eta = \frac{\pi}{180^{\circ}}\frac{y}{\mu + \lambda}\]

Parameters:

mupython:float

Distance from center of sphere in the direction opposite the projected surface, in spherical radii, μ. Default is 1.

lampython:float

Radius of the cylinder in spherical radii, λ. Default is 1.

Attributes Summary

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

Attributes Documentation

lam = _ParameterDS('lam', value=1.0)

mu = _ParameterDS('mu', value=1.0)

param_names = ('mu', 'lam')

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.