This tracklog was recorded by MaxIm/CCD using a 900mm focal length guidescope with the SBIG ST-4 guider. The Y offset values are moved up 0.5 pixels on the vertical axis to separate them from the X offset values. For both axes, the average error is a bit less than 0.5 pixels, peak-to-peak.

Chart 1200 GTO, No PEM, UT6:17:31

A small periodic error is visible in the X offset data at about 6-7 minutes period. Attempts to remove this with the mount's periodic error correction playback have not been successful (so far). How concerned do I need to be about this amount of error?