@lapser
Usability of SX50 with universal camera adapter is questionable, because the width of the lens probably bigger than the width of the eyepiece, but I'm not sure .If you're buying nonetheless universal adapter, Ask for the maximum applicable thickness of the camera with extended lens.
Have you tried to mount the webcam, with removed lens on your catadioptric telescope. I've got good shots of the Moon with cheap web camera, in the prime focus.Prime Focus method always gives a larger increase than what can be obtained using eyepiece and camera lens by afocal method.