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Old 23-11-2013, 11:07 AM
clive milne
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clive milne is offline
Join Date: May 2011
Location: Freo WA
Posts: 1,443
Originally Posted by Peter Ward View Post

I look at it this way....if an optical system is, to coin an old chestnut, is barely "diffraction limited" then *even the slightest* seeing distortion, by definition makes the images it produces, poorer than that limit.

If on the other hand, the optical system is better than "diffraction limited"
(yes... this is possible) it can suck up, for example, a 1/6th wave of atmospheric distortion before *total aberrations* take it into the 1/4 wave "diffraction limit"

Hope that makes sense
it would be relatively easy to demonstrate the currency of your argument (that the AP RH) produces an intrinsically sharper image at focus compared to a Newtonian or SC, by providing a planetary image taken with it so we can do a real world comparison.
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