Zenithal¶

class astropy.modeling.projections.Zenithal[source] [edit on github]¶

Bases: astropy.modeling.projections.Projection

Base class for all Zenithal projections.

Zenithal (or azimuthal) projections map the sphere directly onto a plane. All zenithal projections are specified by defining the radius as a function of native latitude, $R_\theta$ .

The pixel-to-sky transformation is defined as:

$\phi &= \arg(-y, x) \\ R_\theta &= \sqrt{x^2 + y^2}$

and the inverse (sky-to-pixel) is defined as:

$x &= R_\theta \sin \phi \\ y &= R_\theta \cos \phi$

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Zenithal¶

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