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cctran and ccmap rotation

Sean wrote on Oct 17, 2009

Hello,
I was using the IRAF task ccmap to create a linear plate solution for a known astrometry field. I then tried to check the solution by setting the xrotation, yrotation, xmag, ymag, etc. in cctran and inputing the pixel coordinates of stars in my astrometry field along with a known reference coordinate. However, cctran did not reproduce the world coordinates of stars in my astrometry field. When I set the xrotation and yrotation parameters in cctran to 360-(what ccmap reported), cctran did reproduce the world coordinates of the stars in my astrometry field. Am I doing something wrong, or is the rotation reported by ccmap clockwise where cctran expects counter-clockwise rotations? Thank you.

-Sean

Last post on Oct 17, 2009