Decided to follow Marcus' lead on a largish Galaxy imaging RC....
......and finally pulled the trigger on the one of these
http://www.alluna-optics.com/Ritchey...Telescope.html
( the RC 16)
Given the non-trivial expense, I have to say I did a fairly extensive cost-benefit analysis.
The features that swayed me from the other main contender (a 17" CDK...also an excellent 'scope ) were:
interferometrically certified, Zerodur zero expansion optics with an 18 point flotation cell
92mm field corrector with a tighter spot size across a 65mm field than the CDK
Significantly less off-axis vignetting than the CDK
All reflective native configuration allowing deep I/R and UV imaging
Surprisingly only 7% less light collection ( than the aperture driven 14%) compared to the 17" due its smaller secondary.
100mm diameter instrument/camera adapters
dedicated 4" focal reducer-corrector allowing imaging @ F6
Automated focus tracking
Automated thermal control
Robotic mirror cover
Now the wait....
........ delivery takes around 6 months....updates to come
