Quote:
Originally Posted by anj026
At the risk of going off topic, wouldn't a 15 or 16 inch aperture newtonian be required to achieve an un-obstructed 6 inch aperture with an off axis mask?
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That's right, you can turn a 12" dob into a roughly unobstructed 4.8" reflector. Alternatively, you can make a multiple aperture stop with 2-4 holes which kind of re-introduces the central obstruction but could slightly increase contrast (by darkening the background) & sharpness. Both methods didn't work that great for me. Also keep in mind that multi-coated lenses transmit more light than combinations of mirrors, for some reason most people don't seem to take this into account when comparing refractors to reflectors.