Pix2Sky_ConicOrthomorphic

class astropy.modeling.projections.Pix2Sky_ConicOrthomorphic(sigma=90.0, delta=0.0, **kwargs)[source] [edit on github]

Bases: astropy.modeling.projections.Pix2SkyProjection, astropy.modeling.projections.Conic

Conic orthomorphic projection - pixel to sky.

Corresponds to the COO projection in FITS WCS.

See Conic for a description of the entire equation.

The projection formulæ are:

\[\begin{split}C &= \frac{\ln \left( \frac{\cos\theta_2}{\cos\theta_1} \right)} {\ln \left[ \frac{\tan\left(\frac{90^\circ-\theta_2}{2}\right)} {\tan\left(\frac{90^\circ-\theta_1}{2}\right)} \right] } \\ R_\theta &= \psi \left[ \tan \left( \frac{90^\circ - \theta}{2} \right) \right]^C \\ Y_0 &= \psi \left[ \tan \left( \frac{90^\circ - \theta_a}{2} \right) \right]^C\end{split}\]

where:

\[\psi = \frac{180^\circ}{\pi} \frac{\cos \theta} {C\left[\tan\left(\frac{90^\circ-\theta}{2}\right)\right]^C}\]
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

param_names

Methods Summary

evaluate(x, y, sigma, delta)

Attributes Documentation

param_names = (‘sigma’, ‘delta’)

Methods Documentation

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