# Pix2Sky_ConicPerspective¶

class astropy.modeling.projections.Pix2Sky_ConicPerspective(sigma=90.0, delta=0.0, **kwargs)[source] [edit on github]

Colles’ conic perspective projection - pixel to sky.

Corresponds to the COP projection in FITS WCS.

See Conic for a description of the entire equation.

The projection formulæ are:

$\begin{split}C &= \sin \theta_a \\ R_\theta &= \frac{180^\circ}{\pi} \cos \eta [ \cot \theta_a - \tan(\theta - \theta_a)] \\ Y_0 &= \frac{180^\circ}{\pi} \cos \eta \cot \theta_a\end{split}$
Parameters: sigma : float $$(\theta_1 + \theta_2) / 2$$, where $$\theta_1$$ and $$\theta_2$$ are the latitudes of the standard parallels, in degrees. Default is 90. delta : float $$(\theta_1 - \theta_2) / 2$$, where $$\theta_1$$ and $$\theta_2$$ are the latitudes of the standard parallels, in degrees. Default is 0.

Attributes Summary

Methods Summary

 evaluate(x, y, sigma, delta) Evaluate the model on some input variables.

Attributes Documentation

param_names = ('sigma', 'delta')

Methods Documentation

classmethod evaluate(x, y, sigma, delta)[source] [edit on github]

Evaluate the model on some input variables.