Thank you all for the compliments.
Simply put, the gruntiest focuser I could get from Moonlight was the CXL3.6 and it was rated at 10lbs load. Ron told me personally that the Crayford type focusers were not really suited to the heavier astrophotography loads. Because of the design the focuser tube acts as a lever causing the tube to bind. So the only focusers that could handle the weight are the Atlas and the Gemini.
The next problem was backfocus - the Crayford chews up 4 inches, the Fli Atlas 1.25 inches and the Optec Gemini 2.5 inches. (the Gemini does include a rotator) Once you start putting your image train together back focus disappears like magic. The cost difference between the Atlas and the Gemini is USD$1,100
The biggest problem seems to be availability - I ordered the Optec Gemini from AG Optical in April 2015 when I placed the order for the telescope - it wasn't available when the telescope shipped in early November. Which left only the Atlas - which was one reason I went with the image train I am using.
The Atlas removes the weight restriction and the Innovation Foresight On Axis Guider removes the absolute need for the OAG and a rotator to find guide stars. By using the ST7 as a guide camera means I can use the AO-8 and still have room in the future to fit a Reducer should the need arise.
Help
- what started with a C9.25 and a hand me down Mead DSI has mushroomed somewhat.
Cheers
Geof Wingham