RC scopes are the most used by professional observatories as they dont have most frequent optical errors and other advantatges. I like them too. Probably my next scope will be a RC 8" in substitution of the Quattro 8" , too heavy for my age..haha
With the three setups that I use frecuently, exposition is between 5" and 20" they are all short expositions.
The RASA and the RC are mirrors scopes and dont have chromatic aberration I never use any filter IR/UV in there. I only use UV/IR in TS Optics refractor.
TSOptics Ritchey-Chretien 203/1624 for small and weak objects
Tsoptics refractor AP 72/432 (fpl53) for big bright nebulae and other big objects
Carlos,I find that very surprising that you get such good images with 20 sec exposures with the RC at f9. I have a lot of trouble with my sct's at f10 even with focal reducers. I need to reduce to f3 to get an image that is still usually pretty bad. cheers Paul
I can only use the 294 with the 6.3 focal reducer and that is not enough FR on sct's. The 3.3 meade FR and the optec 3.3 are only for the small sensors . I found the fast newtonians gave better images than the sct's. I have never used a RC. They must be very different to sct's cheers Paul