I’m not planning on a field de-rotator but just tuned my servocat using appendix C of the servocat manual so that instead of an object drifting off my cameras chip in 25-30mins , last night I centred in PN NGC6807 and stayed there using the 12mm Nagler @211x /30arc min fov , for 2hrs and10mins
before disappearing behind the neighbours Gum tree. Now I’m wondering how long I’ll be able to push exposure length ( av. to now was 3.2sec) before rotation will he an issue ? I’m thinking an auto guider might be a good ( not for de-rotation) for increased tracking accuracy however I don’t run a computer atm so probably not with the current set up .. thx Gary for the info. Very helpful as usual!!