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Re: [ATM] TDE?

The diffraction ring seems to be a sometimes thing.  Some testers
seem to see it while others don't.  I too see a diffraction ring
only on about 1/2 of the diameter and that is even with a TUE on
one mirror.  The ring is very strong at the middle of the mirror
and tapers off as it gets to the top/bottom of the mirror.  You
can spot some of the diffraction past the top and bottom but that
doesn't go very far.  I'll also note that the couder mask holes
have an assymetric brightness around the hole with the knife side
being the dimmer side.
The tester being used now is a semi slitless (the slit is about
1/8" wide).
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.

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