[rcheshire (Rowland)]

The application is closed loop, driving the RA axis only, to correct mechanical tracking errors.

After a lot of reading on the subject of quadrature encoding, PC- based and camera guiding, the simplest and most effective application seems to be to actively nail tracking accuracy along with refined polar alignment. Accurate pointing is not a goal.

I have a geared encoder assembly in mind, rather than a single wheel. I think the geared assembly has the advantage of lower latency.

The rough maths that I have done indicates that in order to control RA pointing to arc second tolerances, encoder resolution needs to be very high.

I'm not sure that resolution is critical for my application, providing there is adequate direction and speed feedback to schedule commands to the RA motor.

Combined with CCD drift alignment. Corrected tracking should allow for long exposures without guiding.

This seems to be the best and least costly application for a pretty old mount to improve its performance. If finding push-to was an issue, Argo Navis would be my choice, out of convenience.

The FS-2 mod seems incredibly expensive.