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Inoperative focus control

I have a DSX 102 meade telescope that I cannot focus. The focus knob turns several revolutions from stop to stop, but there is no focus.

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I'm assuming this is the Maksukov-Cassegrain telescope. Turning the focus knob CW should get you focus at infinity by moving the primary mirror away from the eyepiece. As you turn the knob it should move in and out relative to the real of the scope. If that's not happening the focus screw may have been turned CW too far and no longer be catching the threads in the rear plate of the scope.

You may be able to get it to rethread by holding the front of the scope toward the ceiling and turning the knob CCW. Attached is a photo of what the scope looks like under the rear housing. To prevent the focuer shaft from turning in too far the knob should be firmly seated agains the rear of the shaft. I think on this model this is a friction fit.

HTH, George
Inoperative focus control - 7793c63.jpg

Posted on Mar 01, 2008


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