Re: ATM 6" Dob: How Easy? How Cheap? How Heavy?

[Robert Duvall <rduvall@jlc.net>]

At 3:08 PM +0000 7/21/98, Brent Hutto wrote:
>OK, so I'd like a telescope. I think a 6" Newt would be very nice and
>a slick Dobsonian mount should work well enough
>
>Then I saw the Sidewalk Astronomers site at
>http://members.aol.com/sfsidewalk/dobplans.htm which makes it look
>incredibly easy to build a plywood Dobsonian mount.
>
>For a 6" mirror in an 8" x 48" tube, is all that 3/4" plywood really
>necessary?

No. 1/2 inch is fine.

>I checked Home Depot last week and a 4' by 8' sheet of
>3/4" birch ply cost 50 bucks and weighs more than my sofa.

I think I used 1 sheet to make my 12.5" scope. You should be able to make a
6" with half a sheet at the very most.


>What are the "hidden" difficult steps in building a basic, ugly
>Dobsonian mount like in the sidewalk 'scope plans?

Look at my 6" plans on my web page. I went pretty cheap on it. Side
bearings are simple storm drains. The base will need to be higher for an
f/8 (I guess that's what you are building), but my design should scale up
easily. I didn't use plywood for my 6", just 3/4" pine boards. Entire thing
is under 20 lbs, made the entire wood parts in 1 evening. My secondary
holder cost about $.10 ;-) a functional helical focuser can be made for
under $3. Eyepieces are the biggest expense.

See my sig for my site.
Good luck. Go for it.



Robert Duvall
Force5 Telescope Making Resources

Software Engineer, Amateur Astronomer (TN),
and General Scientist (according to my son)
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