last night while switching targets from M57 to the veil, auto centering failed displaying a crazy rotator angle (-497.5 degrees), and the auto-centering process simply stopped, leaving the dialog box open all night. the telescope would have tracked into the pier except that APCC saved my bacon. the -497.5 degree angle does not appear in the log anywhere.
there could be an element of user error here, as i have asked for 1 degree rotator accuracy, and the rotator angle is set to 357.5 degrees in the target UI. it is possible that rotator itself may not be commandable to an accuracy of less than 1 degree. i saw this happen once before, so in an attempt to ameliorate the problem i set the rotator angle in M57 to the same as the veil, hoping that no rotator correction would be necessary. the veil nebula angle of 357.5 was auto-populated from the solution of a prior image and i never thought to sanitize it if that’s indeed necessary.
there seems to be some relationship to the plate solving. for some reason PS2 occasionally fails on the veil field and falls back to local ANSVR. as mentioned the initial centering on M57 uses the same angle and i watched it working - i believe PS2 solved everything in that centering run. however on the veil the backup solver was called at least once.
attached is the log and a screenshot of the centering dialog box as i found it this morning.