[mental4astro (Alexander)]

Greg,

This GSO is a "classical" Cassergrain (CC of the purposes of this post). RC's are also Cassegrains... (dah...)

The differences are a few, for which one needs to then make their own judgement as to which optical system best suits their requirements.

* A CC will have a smaller central obstruction & smaller diameter baffle on the primary.

* A CC is typically slower in focal ratio, anywhere from f/10 to f/20

* An RC will often have focal reducers and field flatteners made for them. CC's can have field curvature issues depending on the design of the primary and secondary mirrors. This field curvature has been rectified with other designs, such as the RC, Dall Kirkham, Klevtsov, and even the Schmidt and Maksutov.

* RC's were designed as a photo instrument from the first instance. Visual use is a secondary concern.

There is no one perfect instrument. And every person needs to then evaluate each design on its merits for what their own purposes are. I have tried to give an unbiased summation on the properties of each, and NOT give a pro and con for the very same reason above that each person needs to make their own call on the suitability of any given design. Some people only want photo, others visual and other a bit of each...

What does not change is $$$ will often influence the final quality, or average quality of mass production instruments, an this includes mechanical as much as optical.

Alex.