Kurt, Actually the polar scope is removed and the encoder shaft screwed in using the thread on the RA shaft for Vixen GP/GPDX and the Chinese clones. A closer look indicates they are actually using a 5000tic/rev encoder with some pretty clever signal processing to achieve very good accuracy. I'm thinking of taking a punt that its legit and getting one for my Vixen GPDX, better than a mount upgrade ($$$'s) or autoguiding (way too much fuss and just as many $'s as this thing appears to be). The encoder will need to piggy back on the encoder I currently have install for the DSC's so it might be a bit of a challenge to mount the former's stator. Cheers David On 2008-08-06 17:39, Canopus56 wrote:

David, That's a really neat idea to use the polar alignment scope coupled to an autoguiding camera to control drift. I wouldn't have thought the polar drift was sufficient around a high latitude polar star to accurately regulate drift of a target object near the celestial equator. It looks similar in principle to SBIG's seeing camera box, that works by taking a continuous image of Polaris. Again, some pretty imaginative engineering. Hope to see more of it as the product becomes commercially distributed.

- Kurt

P.S. - The manufacturer website has too much of an "underconstruction" feel to it. Neither of the two European dealers listed on the manufacturer's website actually list the product.