Do you have back and forth rock in your rack and pinion focuser? I did and I fixed it with about $15 worth of parts. The illustrated story, below. At the bottom I have a parts list and step-by-step instructions if you want to do this on your own.
My Celestron C6-NGT is not a big light bucket but it is reasonably portable and that means I can plant my eyeball on her at a moment’s notice. I don’t need to invest a whole evening to enjoy a cup or two of coffee while gazing; I just drag the gear out to the back patio and viola, I’m entertained! The simple design of this Newtonian with a rack and pinion focuser makes the gear accessible, unintimidating and a big hit at parties. At our annual Christmas blowout in 2011 we had a line of people 10 deep for 4 hours waiting to check out Jupiter. For some, this was their first time looking through a “real” telescope.
While my scope gets a lot of use, Celestron did not count on me abusing this equipment when they designed the focuser. After about 10 sessions connecting a digital camera to my scope I began to notice rocker in the focuser draw tube. I must admit that I hung the afocal adapter off my Baader-Hyperion glass hand grenades, wrecking this focuser pretty good, as you will see below. I could calm the movement somewhat by clamping down on the focuser lock but that created more problems. First, it only stopped the movement in the N/S direction. E/W was still full of play unless I really tightened the lock like an animal. Second, this worsening condition effectively meant I could not collimate the scope. There was enough play in the assembly that the centerline of the draw tube moved each and every time I turned the knob. When fully extended the eyepiece was wiggling at the top almost an eighth of an inch from side to side! After 3 nights of blurry vision I decided to fix the focuser myself. Let me take you through the process. If your rack and pinion focuser is anything like mine you should be able to breathe new life into your eye for the sky.
Figure 1: The Culprit, two screws removed
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