Image orientation / Astrometry

[AstroT]

After performing the plate solve process, where in AIJ, can I see (which parameter) by how many degrees the image x (or y) axis has rotated relative to sky north direction?

[karenacollins]

That information is generally encoded in the "CD" matrix terms that are added to the fits header as part of the plate solution. I'm not sure there is a direct indication of rotation relative to sky north.

Karen

[karenacollins]

Actually, I wrote too soon. After plate solving, if you go to Image Window > WCS > "Set north and east arrow orientations for images without WCS", you can read off the offset of north from the Y-axis. You may need to turn image rotation off to get the correct answer.

Karen