Mounting an electric focus motor.

[Bart]

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. :D

[lazjen]

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.

[multiweb]

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.

[jwoody]

I have it on the micro shaft also on the Baby Q and the 65Q.
Seems to work fine for me also

[Bart]

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.

[Merlin66]

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.

[Bart]

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?

[Bart]

Bump!

[jwoody]

I mainly use APT but have started using SGP recently and results have been consistent.

[lazjen]

I don't have enough data points to indicate consistency, however so far it looks good. I also mainly use APT.

[NeilW]

I have mine on the 10:1 and seems to work pretty consistently with SGP although I haven't tried any autofocussing as yet.

[Merlin66]

Neil,
How do you mount the motor bracket onto the Crayford focuser body??
Any images?

[NeilW]

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.

[Merlin66]

Neil,
Ahhh, that makes sense.
I can't see how it can be done with the curved surfaces....

[Bart]

Look here for the mounting info

http://www.iceinspace.com.au/forum/showthread.php?t=112059&page=3

[NeilW]

Yep, that's the thread I was referring to. This is what I used....

[NeilW]

And this is the focuser I'm using http://www.teleskop-express.de/shop/product_info.php/info/p3945_MONORAIL-2--Refractor-focuser---e-g--for-Skywatcher-96mm-flange.html