Thanks Marc.... no AO, just OAG here... unless someone makes an AO with a thickness of 1mm, won't be happening anytime soon here
Damn newts....
I just realised today also, I'll be limited a bit in rotating the whole she-bang on the focuser, as the OAG stalk will foul on the focuser in places, and the motor hanging off the filter wheel will foul on the focuser stepper motor in other places.... Damn newts....
At present I'm using a fairly small chip, so I have fair bit of lee-way with moving the prism, I think I'll work out where it vignettes, then back off a tad. I'm not expecting to have too much hassle finding guide stars through an f/4 at 800mm FL... hopefully!