Re: [ATM] sonotube for telescope

[George Anderson <georgea@cam.org>]

With 1/2" baltic birch baffles every foot or so you should be able to
make the sides of the tube out of 1/4" apple-ply. For additional
strength add gussets inbetween the baffles along each seam of the
octagonal tube. Use plenty of glue and assemble with wire brads and you
should be able to apply a clear finishwith virtually no sign of the wire
brads showing.
But then I like the look of wood...    :^)

George Anderson
Montreal Canada

Clear skies and good health

Richard Klappal wrote:
> 
> 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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