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Replacement teflon pad in focuser housing


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This is a very cheap looking, non-metal focuser that was part of my Celestron 4.5" reflector starter scope. The tube was quite sloppy in the housing so I took it apart (you have to remove the secondary mirror with its holder first, that's two screws). There were 3 pads, at 120 degrees apart, about 10mm wide and running all the way down the length of the focuser housing inside surface. I removed one and superglued down a new teflon pad, 1mm thick and otherwise similar dimensions. The focuser drawtube is now very snug in the housing, no slop at all, and it's not too hard to rack it in and out. When I put everything together, collimation was freakishly out (out-of-focus Venus looked like gibbous moon)! So I collimated the secondary for the first time ever, just aligning the sight tube's cross-hair with the mirror centre spot. I will star test tonight, if possible. I've also noticed a scratch on the secondary but I can't do anything about that, yet. Next, to properly attach the stepper motor for the focuser and test with a webcam!

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