Sorry there is no free ride to be had here. The main problem from the RGB chain is you end up with 3 different spot sizes at three different focal lengths, and slightly different field curvatures.
Trying to register them is nigh impossible....
That said, a single narrow band channel, eg. H-alpha could be tack sharp provided the optics have no spherical or similar errors.
Last edited by Peter Ward; 07-12-2017 at 08:07 PM.
Reason: ipad keyboard
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