RE: [ATM] sonotube for telescope

["Richard Klappal" <klappal@xnet.com>]

David:
	It is a good idea to design baffles for the inside of the scope to prevent
loss of contrast from stray light. They can be made from thin sheets of wood
with an octagonal exterior and a central hole, that will serve the dual
purpose of baffling the stray light and providing the support to maintain
your tube shape.

Rich


-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net]On Behalf
Of David Williams
Sent: Monday, 14 June, 2004 21:22
To: atm@atmlist.net
Subject: [ATM] sonotube for telescope


Hello

I had an idea that I could make an octagonal cross-sectional extruded piece
of tube made out of 3/4" plywood.  I got an Amish owned wood working company
that built coffins to cut the edges (it was something like 72.5 degrees).

Any way it fit together for a while (I had it screwed together) and then it
started to colapse.  It wasn't their fault, it was just too heavy and not
strong enough.  So I am looking for a better way to make a telescope tube.

I found a concrete company in Sturgis, MI a city nereby that has 24"
diameter by 12'.  My telescope is 20" in diameter (the mirror)  and the f #
is F 5 so it is 100".  I could cut it to 8' which is 96".  This seams okay.
Do you think that the wall thickness is allright at 3/16"?  I have a Jeep
Cherekee.  Do you think that I could put the 8' section on top and the 4'
section inside?

Thank you for your help.

David Williams
dwilliams1128@earthlink.net
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