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Old 04-11-2016, 07:40 AM
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Mounting an electric focus motor.

Hiya! For those that have a SharpSky Pro, have you mounted it to the main shaft or the 10:1 shaft. I know David's suggestion is 10:1 for fine focus, and I did pull the focuser mechanism off and lube and retension etc and should all be good providing repeatability however; its the repeatability that concerns me. If it was on the main shaft it would technically never have slippage as long as the rack was engaged. I'm think Robofocus suggsets main shaft for this reason.

Looking for feedback before I continue with the project. Any advice welcome, including from people who have mounted other brands.

Thanks.

Last edited by Bart; 05-11-2016 at 05:41 PM.
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Old 04-11-2016, 10:48 AM
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lazjen (Chris)
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Mine is setup on the 10:1. I haven't used it enough to notice any slippage issues. It felt quite robust though.

I'm still tuning my autofocus routine/setup with it to see how it goes from session to session (and I guess during a long session too). The results of that though will be a while off yet, even if the weather ever becomes good enough to go out.
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Old 04-11-2016, 10:51 AM
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multiweb (Marc)
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Quote:
Originally Posted by Bart View Post
Hiya! For those that have a SharpSky Pro, have you mounted it to the main shaft or the 10:1 shaft. I know David's suggestion is 10:1 for fine focus, and I did pull the focuser mechanism off and lube and retension etc and should all be good providing repeatability however; its the repeatability that concerns me. If it was on the main shaft it would technically never have slippage as long as the rack was engaged. I'm think Robofocus suggsets main shaft for this reason.

Looking for feedback before I continue with the project. Any advice welcome.

Thanks.
I'd recommend 10:1 rather than the main shaft. In case the focuser locks, it's better to have some slippage than stripping the smallest motor gear, or you'll be up for a new motor.
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Old 04-11-2016, 08:28 PM
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jwoody (Jeremy)
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I have it on the micro shaft also on the Baby Q and the 65Q.
Seems to work fine for me also
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Old 05-11-2016, 06:11 PM
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Thanks for the replies so far. I remaned the post to see who else has what mounted where. I see in equipment discussions a Robofocus mounted to the main shaft.

Last edited by Bart; 05-11-2016 at 08:33 PM.
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Old 05-11-2016, 06:27 PM
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I don't understand why you would think the 10:1 gear system would be less reliable than the direct drive?
I have my electronic motor belt drive to the fine knob. No issues, no drama.
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Old 06-11-2016, 08:31 AM
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Hello Ken. If it were indeed a gear system that coupled to the shaft, I would be ok with that as that would be constant mesh. The system uses a planetary ball set and relies on friction to drive the focuser.

To those that have replied, who are using it as an automated focuser with Maxim DL and FocusMax or SGP and have 100% repeatable results?
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Old 07-11-2016, 01:15 PM
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Bump!
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Old 08-11-2016, 07:19 AM
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jwoody (Jeremy)
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I mainly use APT but have started using SGP recently and results have been consistent.
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Old 08-11-2016, 10:50 AM
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I don't have enough data points to indicate consistency, however so far it looks good. I also mainly use APT.
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Old 08-11-2016, 12:11 PM
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I have mine on the 10:1 and seems to work pretty consistently with SGP although I haven't tried any autofocussing as yet.
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Old 08-11-2016, 12:34 PM
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Neil,
How do you mount the motor bracket onto the Crayford focuser body??
Any images?
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Old 08-11-2016, 01:22 PM
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I'm at work at the moment, but I'll take some pics when I get home. There's a huge discussion on this forum a couple of years back about trying to fit a SharpSky to a Bintel crayford, but it seemed like quite a big job, and I don't have tooling nor expertise to achieve it, so I had to find a focuser that had a flat underside, then make up a plate with some spacers to fit.
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Old 08-11-2016, 02:23 PM
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Neil,
Ahhh, that makes sense.
I can't see how it can be done with the curved surfaces....
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Old 08-11-2016, 04:16 PM
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Look here for the mounting info

http://www.iceinspace.com.au/forum/s...=112059&page=3
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Old 08-11-2016, 07:51 PM
NeilW
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Yep, that's the thread I was referring to. This is what I used....
Attached Thumbnails
Click for full-size image (SharpSky1.jpg)
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Click for full-size image (SharpSky2.jpg)
99.9 KB26 views
Click for full-size image (SharpSky3.jpg)
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Old 08-11-2016, 07:56 PM
NeilW
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And this is the focuser I'm using http://www.teleskop-express.de/shop/...mm-flange.html
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