I use the "Darv" method, where you use your camera, set for a 60 sec exposure, set the handset speed to 1 and slew for 30 secs (RA axis) in one direction then slew in the other for 30 secs. You adjust the mount till you get a straight line in both directions.
https://www.cloudynights.com/article...ert-vice-r2760
Rick