Hi Ken,
I'm getting ready to overhaul my scope (the parts have arrived) with new focuser and other bits & bobs. More out of curiosity than anything else I'm tempted to dabble on the dark side and put 0.5X reducer and a camera on the back of the MK91 and also point it at moon with a M4/3 sensor on the back, as I already know what this scope is capable of photographically (
http://www.astronominsk.org/Moon/Moon2009_en.htm)
What would you suggest for autoguiding at focal lengths of (a) 1500mm and (b) 3100mm (c) circa 6000mm ?
Mount is an AZEQ6. I have a 70mm f/6.7 APO and a cheap 80mm f/10 that can be pressed into guiding duty but open to other ideas...