This is the raw mechanical autoguiding quality of the AP1600GTO mount https://pbase.com/strongmanmike2002/image/173146544/original
loaded with ~50kg of payload and ~50kg of counterweights, after polar alignment using a polar scope only, no PEC,
no Absolute Encoders, no ProTrack and no T-Point in use. These are three guide star centroid plots from three separate
nights throughout the year. The guiding image scale is 3 arc sec/pix, so average guide errors ranging from
0.05pix to 0.07pix equates to average guide errors of between just 0.15 and 0.21 arc sec!