Last updated: 15 February 2009
Sent:	Sunday, February 15, 2009 14:42:11
From:	R. G. Rienks (
Your site has been valuable ever since I first discovered it. As a
satisfied owner of an ETX-90EC I found the content well worth the read.
THis little scope has traveled with me where ever I go and was my main
scope while residing at 20 N - Puerto Vallarta. A great local for
watching Crux rise over the Southern horizon.

I did notice a certain wobble in the tripod when raised for equatorial
tracking but I just lived with it. Until recently. I picked up a
Celestron 8 in a fork mount less tripod. Since my tripod was the stout
Meade offering with 1.5" tubular steel legs and the tilting platform I
ventured to adapt it to  accommodate the larger scope. The wobble in the
tilt platform became much more of an issue as the larger scope tracked
across the sky.

I decided to remedy the wobble. I went through every site I could and
arrived at a decision: The assembly was too loose due to the bolt being
fitted to oversize holes in the Eq assy. I'm sure you know what I mean.
Being cheap, I settled on bushing the holes. The hole were about 5/16"
in diameter, allowing the slop that annoyed me.

The Solution:

1.) I purchased one bronze bushing, 3/8 x 1" ($2.13). This I cut in
half, crosswise to give me 2 at 3/8 x 1/2".

2.) I also bought 2 ea. 1/4 x 1" stainless hex head bolts with lock nuts
and 4 washers ($0.77).

3.) Starting with a 5/16" drill bit I worked up to 3/8" by 64's,
drilling each hole carefully to avoid tilting. This was done on my drill
press. Working up in small increments was to minimize the chance of
inducing error.

4.) Final fitting of the bushing sections was accomplished by gently
scrapping of the interior of the new holes using a narrow triangular
scraper. The same effect can be had by scrapping with the edge of a
triangular file - not by using a filing stroke. After each bit of
scrapping, test the fit, carefully, until it just slides into the paired

5.) The 1/4" bolts are there to hold the ears together and need not be
cranked down tight. Just firm.

The end result is no play or wobble in the assembly with either scope
mounted and tracking in RA. The tripod was pretty good value for the
money (included with the scope) and is now more satisfactory.

R. G. Rienks,
Baker Valley Astronomers, The Trail Gazers
Trail Gazers is an organization of unorganized astronomers, open to all,
no dues, no meetings. The url takes you to the site established by
Melody Crist. Thank her for her efforts by adding your information to
the site. She is the force behind Trail Gazers.

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