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

[Steve Vegos <yovw@cdsnet.net>]

Hello Brent,

Don't forget primer, paint, a bunch of cheap brushes for the outside of the
tube and the base.  If you have exterior paint lying around (polyurethane
enamel works great) then you're off the hook.  Krylon Ultra Flat Black PN
1602, couple cans for the inside and anything that goes in the tube.
Contact cement to attach the ebony star to the bearing surfaces.

Save some money and use "extra" plywood parts to make your own mirror cell.
 And if "ugly" is ok then use AB fir plywood and save yourself $25.00.  I
think CD is to rough and has to many voids allowed in the grade to be
useful to you.

I built a single stalk mirror holder out of $2.00 worth of brass.  It's
.125" thick and curved to spread the diffraction over a wide area.  This
eliminates the heavy spike from single stalks. (I hear the cringing and
growling out there).  The mirror end is a brass flat filed oval and
soldered on. The mirror silicones to this oval.  The other end has a 3/16"
O.D. brass tube soldered on as a sleeve to fit in "holder hole" found on
the cheap 1 1/4" focusers.  Worked well last night when we star tested the
blank we're...having ...trouble ...with.

You'll need a finder, Telrads at $40 are great.  1/2 a binocular from a
pawn shop at $10 would work ok too.  Find one out of collimation and have
the proprietor look through it.  Makes the price fall with out a lot of
haggling.  My "mono" mount is curently under construction, but consists of
two 2 1/2" rings of aluminum, drilled and tapped 120 degrees apart.  These
will be mounted on a 1/4 piece of plywood with the eyepiece ring offeset
above the objective ring for easier access.  Not done with it and I haven't
tried it but I'm optimistic it will work out ok.
 
Eyepieces, mirrors, focuser go in there too.

Two things I didn't do and should've:  

Put the ebony star on the bottom of the rocker box and the teflon on the
top of the ground board.  Dirt and dust won't sit on the ebony star and
grind at your teflon.

Make feet for the ground board.  I put little circles of wood on the bottom
and they were ok, but not good.  Made 3 feet out of 2x6 on edge cut like
the letter L, glued and screwed the long back of the "L" to the ground
board and the "hook" of the "L" points down to the dirt.  Works great.

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Two things I did and was glad I did:

Made a "cradle" for the tube to rotate and slide in.  Allows the eyepiece
to be rotated for comfort and the tube to slide for balance.

Didn't grind a mirror for my first telescope.  Still wouldn't be looking at
anything. :{


Steve Vegos