[ATM] RE: Is my mount right?

["lou krajci" <loukrajci@comcast.net>]

From: "David  Williams" <dwilliams1128@earthlink.net>

>I am making a 20" telescope and I posted pictures of the progress on it at
this site
>http://www.atmlist.net/contrib/dwilliams1128-at-earthlink-dot-net/
>and then you click on 20"Telescope Stuff and there are the pictures.

>On some of the pictures you can see the plywood structure that I used as a
mount for the primary >mirror.  I  have used a layer of 3/4" thick weather
stripping in a circle shape and then as a
>cross shape in the middle.  I was wondering if this is orthodox procedure
in the atm list.
>Probably though I should use a floating point mirror cell or Plop, but I
don't know much or
>anything about either one of these things.

See:  http://www.efn.org/~mbartels/tm/largthin.html as one starting point.

If you don't know about mirror support, then you have two options:
A.  Find a working design that you can copy with no substantial changes,
such as in this book:
http://www.willbell.com/tm/dobtel.htm
(actually any book at:  http://www.willbell.com/tm/index.htm may be helpful
for you)
B.  Learn about mirror support, and then design your own.  See:
http://overton.tamu.edu/aset/krajci/ and look at all pages dealing with
mirror support, including
http://overton.tamu.edu/aset/krajci/scope-design.htm especially at the
bottom of the page titled "Main Mirror Cell - sloppy moving parts"...and
then look at
http://www.foothill.net/~sayre/ and study his mirror support for his 22 inch
telescopes.

I hope this helps.

Tom Krajci
Albuquerque, NM

PS.  How thick is your mirror?  That's important information to design a
proper mirror support.  The next question is what is it made of...plate
glass?...Pyrex?...other?
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