Quote:
Originally Posted by gregbradley
RCs and Dall Kirkhams are not good visual instruments usually having quite a large secondary obstruction.
But they are much better than SCTs for imaging. A 10 inch carbon fibre RC would be a very good imaging instrument although the focuser may need to be replaced unless you are using a lightweight camera. I checked out the 12 inch at Bintel and its an impressive scope except for the focuser which you can flex by hand easily. Still that is a well known issue with these GSO RCs but the optics are very good and I have been continually impressed with the quality of images they are producing. Plus the dielectric coatings have very high reflectivity, don't scratch and the carbon fibre truss seems very high quality.
A 12 inch GSO RC with a Sony 694 or a KAF8300 chipped camera would be capable of a lot. It would need an off axis guider to cope with the long focal length guiding.
Greg.
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I disagree.
The Mewlon 250S I had, which is a Dall-Kirkham design, was a very good visual instrument. Granted the central obstruction of the secondary was 28% but this is significantly smaller than the 40% + the RC has.