Re: [APML] Novak cells, clip diffraction patterns (was Alnitak)

[Torsten Clay <tclay@theriver.com>]

Well, I can't easily measure the size of my mirror clips without
disasembling the whole scope, but I think the clips are about 1/4" wide
and go about 1/4" into the mirror. There are also 3 postage-stamp shims
(slightly smaller) between the corrector elements and not aligned with the
mirror clips. They are all visible to some extent when I collimate the
scope.

My secondary mirror is mounted from the corrector, so I don't have spider
diffraction spikes. The corrector cell is also slightly smaller than the
mirror diameter, so the very edge of the mirror is masked. But I looked at
my photos again, and I do see a little of a "notch"-like feature in the
brightest stars.

Torsten Clay
http://personal.riverusers.com/~tclay/


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