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Old 23-09-2009, 08:22 PM
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marki
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Duncan the RC will deliver a larger illuminated field for your CCD as the secondary mirror is quite large (at the cost of contrast). Field curvature and is still present and can be corrected with a lens (flattener). RC scopes have hyperbolic mirrors which has kept them so expensive for so long as they are difficult to make well but they are coma free. As Peter Ward has shown APS size chips will not show much vignetting on the GSO scopes (from his cropped samples) without a flattener, it is more evident when you use the monster chips. I would not thumb my nose at a Mak Newt either as I have seen terrific pics from these scopes but as the secondary is smaller and I think there would be a greater amount of vignetting present. The Mak newt will be longer whilst the RC will be more compact (mount vibration). You also really need to consider the type of objects you want to image in respect to the different focal ratio's (F8 Vs F4?).

Mark


Quote:
Originally Posted by toryglen-boy View Post
i was led to belive it was the opposite mate, the nature of the optical train gave a flat image, and there where no "correctors" in there at all !!

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