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Subject: [M]: Thanks! Re: Someone broke my scope! HELP please.
From: Darren
Reply To: mapug@shore.net
Date: Wed Jan 28 01:29:26 1998
A big THANK YOU to all who have responded to my post!
I think I've fixed the scope... though I'm not sure if it is as good as
before... really can't tell.
I had to use a flat screw driver wrapped with white plumbing tape to pry the
corrector out. Then I examined the secondary housing and thought, heck, I've
already lost the rotational orientation (of the sec. housing), so I
unscrewed the baffle. The outside half of the housing then comes out,
together with 2 gaskets (cardboard-like rings).
So I ended up with just the cored corrector plate. This was my first time
removing the corrector. A good opportunity to clean it, though I really
couldnt get rid of water marks, even bottled distilled water left marks. I
was also able to use a blower to get some specks off the primary.
Oh yeah, and it turned out that the corrector seemed tightly stuck not
because of the cork shims (since it was a easy fit when I replaced the
plate), but instead, it was because the plate and the black surface which it
rests on behind, somehow became cemented. Lots of black specks still stuck
to the glass around the edges when I removed it.
One thing worried me though... When I examined the secondary mirror, I
found it slightly but noticeably off-centre in its housing... and to think
I've lost rotational orientation... oh no...
Also, the secondary mirror seemed less "bright" than the primary, perhaps
slightly hazy? or is it simply because of its size and curvature that makes
it seem less bright than the primary.
No problems with screwing together the secondary housing, 'cept that I
wasn't sure how tight to make it. The corrector went back easily, I lined up
the marks, no problems...
The scope was way out of collimation though... I did a rough collimation in
the day using Al foil and a lamp to make a 'star' then refined it somemore
last night with procyon. The scary part is over-tightening the collimation
screws or letting the secondary drop off.... At times, it took a lot of
force to turn the screw clockwise.
Anyway, I've collimated as accurately as I could... just by judging if the
"hole" of the "donut" was centered. Perhaps I'll be able to do it more
accurately with some kind of reticle or micrometric eyepiece?
Hopefully, the optical quality is as good as before... and I'm happy to have
saved exorbitant repair fees while at the same time learning more about my
scope.
Thanks!
Happy holidays! (to some people at least)
darren