# Sky2Pix_BonneEqualArea¶

class astropy.modeling.projections.Sky2Pix_BonneEqualArea(theta1=0.0, **kwargs)[source]

Bonne’s equal area pseudoconic projection - sky to pixel.

Corresponds to the BON projection in FITS WCS.

$\begin{split}x &= R_\theta \sin A_\phi \\ y &= -R_\theta \cos A_\phi + Y_0\end{split}$

where:

$\begin{split}A_\phi &= \frac{180^\circ}{\pi R_\theta} \phi \cos \theta \\ R_\theta &= Y_0 - \theta \\ Y_0 &= \frac{180^\circ}{\pi} \cot \theta_1 + \theta_1\end{split}$
Parameters
theta1float

Bonne conformal latitude, in degrees.

Attributes Summary

 param_names Names of the parameters that describe models of this type. theta1

Methods Summary

 evaluate(phi, theta, theta1) Evaluate the model on some input variables.

Attributes Documentation

param_names = ('theta1',)

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.

theta1 = Parameter('theta1', value=0.0)

Methods Documentation

classmethod evaluate(phi, theta, theta1)[source]

Evaluate the model on some input variables.