ETX TECHNICAL TIPS Last updated: 24 November 2003

Yet Another Homemade Pedestal

Sent:	Friday, December 22, 2000 16:27:14
From:	plloukota@juno.com [no longer valid]
After a bit of investigation, I came to the conclusion that the Mead #833
tripod and the ETX125EC weren't made for each other.  I think that the
scope is a bit too heavy for the tripod mount when in the Polar Mode.  
Therefor I decided to build something that was sturdy and reasonably
transportable plus being a bit cheaper.  This is what I came up with and
if it'll help anyone else out then that's a good thing.

The actual column is made out of two pieces of 6.25"O.D. sewer pipe
(whole the comments).  As it turns out it's sturdy and doesn't 'cold
flow' ( new sewer pipe is recommend).  The rest of the structure is 3/4"
birch plywood left over from a W.A.E.A. project I did a while back.  The
sector plates for the wedge is made from 0.125" 6061-T6 AL.  Add the
nuts, bolts, Tee nuts knobs, screws, glue etc and the total outlay was
about $30.00. ( I count my time as free but it was about 30hrs of spare
time not counting splinter removal time.  The project was extended a bit
by having to explain almost every step to my 4yr old grandson, but worth
it, even with filling in the extra holes and hammer dents he made while
helping....).

There are two ways to build stability cheaply. One is to build it super
rigid structure and the other is to give it mass.  I did the latter.  I
can fill the column with sand and its as stable as my block wall. (It
does put a bit of a cramp on the transportability though if you don't
dump the sand).

The column is in two sections so the base plate may be located 40" or 26"
above the ground (standing or sitting height).  There is a 5/16" threaded
rod down the center holding the wedge base plate in tension with the
three leg sections.  There is a 3" thick plug joining the two sections
and 3/4" plugs at the top and bottom ends for mounting. The wedge base
and plug also has a thrust bearing made of a sheet of Teflon to
facilitate alignment tweeks.  The three legs are removable by the way
with one bolt and a wing nut each.
The wedge base plate is drilled to mount in two positions.  The one shown
is so the scope CG is over the column in the polar configuration. the
second set allows the plate to center up the CG over the column in the
AX/ALT configuration.

Setup and break down  time is about 5 min providing your grandson isn't
using them to 'fix' the VCR...

I have a AZ and LAT vernier adjustment screw device that I'm working on
and should install soon.  This will make polar alignment a snap. 

Doug

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