fitsmgmt.wcs.make_linear_wcs

fitsmgmt.wcs.make_linear_wcs(cd, shape, crval=(0.0, 0.0), crpix=None)

Create a purely linear (no SIP) TAN WCS from a CD matrix.

Parameters

cd : array - like

2x2 CD matrix in deg/pixel, as produced by local_cd_matrix.

shape : tuple of int

(ny, nx) of the image this WCS describes. Used only to pick a default crpix (the image center) when crpix is not given.

crval : tuple of float = (0.0, 0.0)

(CRVAL1, CRVAL2) in degrees. Default is (0.0, 0.0).

crpix : array - like = None

(CRPIX1, CRPIX2) in the WCS’s 1-indexed pixel convention. If None (default), defaults to the image center, (nx / 2, ny / 2).

Returns

w : astropy.wcs.WCS

A 2-D WCS with CTYPE = ("RA---TAN", "DEC--TAN") and no distortion terms.