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The Crayford and the Can of Worms

Started by mickw, Dec 01, 2011, 09:41:36

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mickw

Last night I decided to strip down the focuser on the Burgess, clean, lube and adjust it to try and resolve the flexure.

The 3 grub screws around the body of the focuser were not as I thought, tensioners, they position the focuser to centre it in the scope - Collimation ? - I have tweaked these previously so I'm guessing that the alignment is now out of whack  :!

The only tension adjustment is a single grub screw at the eyepiece end of the focuser.

With the TS flattener I get focus at around 70mm (almost fully extended) which puts CoG of the Canon about 110mm from the end of the focuser.

I've adjusted the tension and assume the flexure has gone away, or it's too stiff for me to detect.

SO, onto the questions....................................

A parfocal ring would give a bit more leeway  with the focuser but camera will still be 110mm past the focuser - Worth doing ?
Would it be advisable to always have the focus knobs parallel to the ground so draw tube is supported centrally ? - This answer may lead to a new rotating focuser.  :-?




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