Quote:
Originally Posted by Paul Haese
Yeah that is true. This rotation is nearly symmetrical.  Lums taken on the Eastern side of the meridian have this problem more than on the Western side. |
OK, so that points to a balance problem more than anything.
As the camera/OAG will not be balanced around the axis of rotation, do you run an instrument rotator?
Could be minor flexing of the imaging train, rotationally. Try with the OAG vertical, so it's not placing any torque on the rotator/nosepiece etc.
Additionally, you should notice field rotation between subs, no matter the length, I routinely see this as my Polar Alignment is rarely exceptional (imaging stuff just a bit too heavy for the G11). This time you would have to single star align your subs, then if there's any field rotation then it will be around the alignment star. Alternatively, once the subs are registered, flick through them, the edges of the frame will rotate.
Finding the causes of this stuff can be painstaking, but you have to be barking up the right tree to find the problem.
Cheers
Stuart