Here are a few notes from my own experience with the RH200.
First of all, OS ships this unit with no tube rings. A single arm, off-axis mechanical support is wrong if you expect to have any mechanical stability.
A myth: Having tube rings on this telescope does not distort the wave front, or mechanical orthogonal of the system.
The STI guider and lens assembly works like most autoguiders - it measures the centroid of the star image. I use mine on the RH200 without any guiding problems.
Tested: 3nm filters are a no recommend for f/3. Been there, done that. The transmission impact is serious. So much so that my 6nm bandpass shows more nebulae in 600 sec exposures than 1800 sec the exposure through a 3nm filter.
And finally, it's not about wide field, its about very short FL that mandates close attention to the image train, optical collimation, and focus control. It takes a real master to tame the beast.
jg
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