LX200 RA Leaping elimination

Image 1

I observed lately on my telescope (12' LX200 ) a mysterious behavior after some failures on the astrophotography.

The failures happened when at the tracking time suddenly the guiding star disappeared from the reticle eyepiece with a short soft metallic noise present. Of course any photograph was destroyed. The first thought was that a mirror shift happened but after a few tests I was sure the entire fork system was leaping.

Trying to examine what was the cause of the leap I setup the telescope on the wedge pointing to the Polaris without any power and the RA knob released. Surprisingly I discovered that when I rotated the telescope in RA, there was an area around which a leaping was happening. The leaping was happening every time the telescope passed the area where the unbalanced weight of the forks  changed the loading direction of the entire RA system.

In the point the leaping was happening I could see the Polaris drifting rapidly several arc minutes away and also sometimes I could hear the short soft metallic noise.

Note that the telescope was rotating completely free around this area .

Taking courage and some knowledge from Doc G site I completely disassembled the RA mount trying to discover the possible points of failure. I discovered that the house for the upper ball-bearing system was a little wider than the ball-bearing external diameter, permitting a slightly loose of coupling. I then cut a ribbon of single beer canister as you can see in the image and applied it in the gap between the ball-bearing and the housing , eliminating any loose of couple.

I was then glad to see that the problem was completely eliminated.

So folks this is the conclusion : Don't throw your beer's canister away , send them to Meade !!!.

George Nikolidakis

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Last edit: 06.11.2001 .