Sky2Pix_ConicOrthomorphic

class astropy.modeling.projections.Sky2Pix_ConicOrthomorphic(*args, meta=None, name=None, **kwargs)[source]

Bases: astropy.modeling.projections.Sky2PixProjection, astropy.modeling.projections.Conic

Conic orthomorphic projection - sky to pixel.

Corresponds to the COO projection in FITS WCS.

See Conic for a description of the entire equation.

The projection formulae 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.

Methods Summary

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

Methods Documentation

classmethod evaluate(phi, theta, sigma, delta)[source]

Evaluate the model on some input variables.