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# Pix2Sky_ConicOrthomorphic

class astropy.modeling.projections.Pix2Sky_ConicOrthomorphic(*args, **kwargs)

  Bases: `Pix2SkyProjection`, `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 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 `python: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 `python:float`

      \((\theta_1 - \theta_2) / 2\), where \(\theta_1\) and \(\theta_2\) are the latitudes of the standard parallels, in degrees. Default is 0.