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Focuser slipping


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Pointing a Sky-Watcher ED100 refractor high in altitude makes its crayford focuser slip if carrying a heavy 2" eyepiece. The locking screw does not always help as it seems to be not cabable holding the focuser and also it defocus the image slightly when locking. Is there a solution or should I start looking for a new focuser?

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After being plauged with slippage I tried the recessed bolt first and my focuser just slipped out every time the tube went near vertical, I decided to take the whole focuser apart. I found a few problems, loose screws here and there so after a bit of a clean I put it back together ensuring all screws/bolts were in well and then tested it, have not had a problem since :).

Jim

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This precisely why you should not mention the C-word anywhere near Olly Penrice. Rack-and-pinion is much less likely to slip. If I ever add a separate focuser to my SCTs internal mirror-shift focusing, it will be an R&P. On the other hand, the Crayford (hope Olly isn't looking) on my 80mm F/6 easily holds my 2" diagonal and the Panzerfaust (31mm T5 Nagler). If it can hold that 1 kg monster and the diagonal in place, I am OK for the moment.

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Just attach one end a rubber band(s) to the eyepiece locking screw and another to a fixed point further up the OTA and problem solved. :smiley: This is not to suggest that the focuser shouldn't be examined to see if there is an adjustment issue.

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I'm saying nothing, except that a guest here present took two WO FLT98 Crayfords back to the vendor and ended up forking out for a Feathertouch R and P.

I'm not the only one, you see!

More seriously, follow the tweaking advice and you should get the (horrible!) thing working OK!!

I thnk Peter's nicker elastic is a seriously good idea, by the way.

Olly

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Maybe add an electric focusser motor to hold the focus? Less focussing vibration and the motor will help stop the shaft rotating.

Not sure. The one on Yves' ODK (Baader Steeltrack) has enough slack in the belt drive to allow slippage on occasion.

Oly

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