Time Series Tracking Error

Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 03/09/2021 - 17:51

Can someone tell me how the software calculates the tracking error shown in the Time Series Summary?  I am seeing a consistent shift in my X axis tracking data (and not in my Y axis) after a meridian flip.  If tracking error is measured relative to the target star, this does not make sense as I have ACP set up to keep my target dead center in my images.  The summary shows a very flat tracking line before and after the meridian flip just a rather large X-axis shift of about 2000 pixels (as an aside my images are binned 2x2 and I only have 1532 pixels in the X-axis -- so how can I have 2000 pixels of tracking error?).

As an aside, all of my comp stars and check stars are shifted in mag by about 0.1 mag before/after the flip, but I suspect that's just due to the diagonal flip on the CCD chip itself.

Thanks, CCHD