[AstroPy] WCS world to pixel conversion with SIP correction?

Leo Singer lsinger at caltech.edu
Mon Jul 15 21:27:08 EDT 2013


I want to look up the pixel coordinates in a FITS image from the world coordinates (RA, Dec in ICRS), but the image has SIP distortion parameters. I noticed that the function WCS.wcs_world2pix does not perform the SIP transformation, and there is apparently no inverse function of WCS.all_pix2world.

There is this open issue:

Iterative implementation of wcs.all_world2pix

Am I perhaps looking in the wrong place? Is there a sequence of existing function calls to convert from pixel to world coordinates, including the distortion correction?

Leo Singer
Graduate Student @ LIGO-Caltech

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