Are indicated compass directions in VPHOT WCS solved images rotated 90 degrees from true?
VPHOT shows field orientation in the lower right corner of WCS solved images. Two perpendicular lines point respectively E and N. The funny thing is, the orientation of the two lines is rotated 90 degrees clockwise from the compass directions given on my AAVSO chart. I produced the AAVSO chart using the online chart plotter with CCD option, non-reversed. The 90 rotation of WCS compass directions occurs in all fields (six or so) that I've uploaded to VPHOT. (I just discovered VPHOT yesterday. It's great!) I am using an SCT, with 2 mirror reflections.
The result is that what's shown as N should be W, and what's shown as E should be N.
Has anyone else noticed this behavior?
- Andy Howell (HOA)