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Old 21-11-2018, 07:06 AM
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multiweb (Marc)
ze frogginator

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CN-212 focusing

Hi guys, just thinking about the simplest most efficient least intrusive way of achieving motorized focusing of the primary for my CN-212. I haven't decided yet if I'm going to use a direct drive or a belt and offset the motor. It's going to depend on how much room I have sideways at the back once the AO is in there as it's quite wide.

One thing I know for sure is that I won't be drilling the back cell and won't be changing the focuser knob on the telescope. So the solution will be an add on rather than changing or modifying existing parts.

I came across this picture on line. It looks like a plastic sleeve with three grub screws to secure the cover on the focusing know and it also has a geared part for a belt. It was part of a robofocus setup advertised on astromart. Is this part of a robofocus kit or just a third party contraption?
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Old 21-11-2018, 10:12 AM
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Merlin66 (Ken)
Spectroscopy Wizard

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Marc,
Looks like it was "made for a job" and should work....

I used a SW geared motor (the timing belt just wrapped around the existing knob) on an aluminium plate (mounted to the existing finder holes in the OTA)
Simple and effective. Worked well for me....
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Old 21-11-2018, 10:24 AM
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multiweb (Marc)
ze frogginator

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Thanks for the pics Ken. Yeah that's one way I had in mind too. I'd be running off the dovetail with a bracket.
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Old 21-11-2018, 10:42 AM
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LewisM
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Yep, go for it Marc.

Plenty of ways to skin a cat without needing to drill holes or permanently glue things (hint hint Logan!)
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