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Unlocking an Electric Focuser?


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Ok I hope this doesn't sound as daft as it's titled..

Right I've got a dual speed focuser for my 200P & I've recently brought a Skywatcher electric focuser to fit so I can do some imaging or at least have a go.

Well unknown to me I never realised when fitted that you can't use the manual focuser when I'm using the scope for observing. I know I could probably just slacken the grubscrew to unlock it but I think if that was done on a regular basis then either the threads would wear out or you'd end up loosing the grubscrew itself.

Does anyone have any ideas? :hello2:

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Seems to me that the electric focuser was intended for imaging only where you control everything remotely - not for visual observing. In fact, having built my own electric focuser with belt drive so that I could disconnect it easily, I find I don't use it even for imaging (which I do exclusively). I line up a bright star in the frame and focus with the slo-mo knob using APT (or EOS Utils) in live view. Then with Bahtinov mask on scope I adjust focus looking through the window in the dividing door at the monitor in the warm room. Finally I lock the focus with the locking knob and just check that focus is still right. After that focus is fine for the whole sky.

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Tich - I know what you mean. I had the electric focuser on my SW150 and have just added it to the 250 dob. It's a bit of a pain having to use the controls for all focusing. I don't know any way of getting round it I'm afraid.

I just got used to it.

I was a bit disappointed with the quality of the velcro it came with! it peeled off within a couple of uses, the adhesive backing was rubbish. I replaced it with a couple of bits of my own Wilko's velcro - proper sticky :hello2:

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Thanks guys for the tips,

I might see if I can make up some sort of thumbscrew up to replace the grubscrew so I can use it just for observing. I haven't got an observatory so the scope will have to sit outside & I'm planning to have the laptop in the small shed I have so when I start imaging I can focus it all from there as I am able to operate the electric focuser via USB.

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Like Gina I built my own and have a belt drive - this works off the "fine" knob on the dual speed focusser. When I want to coarse focus I just have to slip the belt off and adjust the focusser, belt back on and fine focus with the motor drive.

I really find the complete lack of vibration/movement when using the electric focusser outweighs any slight inconvenience.

Edited by Bizibilder
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The Moonlite high resolution stepper does have a clutch to allow manual control.

Of course its far from cheap. in the end I just got another lakeside and have to deal with the fact I have no manual focus.

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What's up with using the little hand controller? The skywatcher "autofocus" was designed for visual use, not imaging. If it was designed for imaging it would have stepper motors so that focus would be repeatable and the autofocus routines in Maxim and Focusmax would work (I've had no luck with the latter).

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The O ring or belt method might be an option I'll consider in the future when I get another scope, For now it's just fitted as standard so if I want to unlock it I'll just have to undo the grub screw for now.

IMG_0507.jpg?t=1338938469

The standard control unit

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The USB mod unit.

IMG_0516.jpg?t=1338938434

I've just got to find somewhere to put it all. :rolleyes: Thanks for the help guys :grin:

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