Inconsistent definitions of "parity" positive/negative/on/off

dstndstn / astrometry.net

Astrometry.net -- automatic recognition of astronomical images

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Inconsistent definitions of "parity" positive/negative/on/off #168

Open dstndstn opened 5 years ago

dstndstn commented 5 years ago

ugh, solve-field reports something different than wcsinfo, and solve-field accepts input in yet another way. and the web site...?

swtnikita50 commented 9 months ago

Hey dstndstn, I think I am facing this issue. The website is report -ve parity for an image, while using wcs.fits file, I am getting a +ve parity for the same file. Did you get the answer to this?

dstndstn commented 9 months ago

Parity is defined as sign(det(CD)), ie, based on the CD matrix of the WCS header.

If you use FITS vs JPEG images, things get confused because of a vertical flip between display conventions in those image formats.