Electric focuser for ZS66, adapter skywatcher version.

[Astroboffin]

Hi,

I wanted an electric focuser for my William optics ZS66SD but there is not a dedicated one available, well unless you want to spend £300.

So I thought I would buy the £45 skywatcher one and adapt the bracket to fit, how hard can it be....

Well here's the results in cas anybody is interested.

The one thing I will say is that when fitted you can't use the hand focuser , as the motor will not turn by hand, so if I need to do that, then I have to loosen the grub screw that holds it to the focuser shaft.

Not a real issue really.

Anyway here are some pics, let me know what you think.

Remove focus knob, tension locking ring and focus lock nut.

Fit electric unit onto shaft, tighten grub screw

Marked out and drilled new holes in bracket to match fixing points on focuser

Check it fits correctly

Fit all screws to secure bracket to motor

All done and tightened up bracket re painted to cover file marks, and finished.

AB

[Astroboffin]

The last image just shows what it looked like before...

AB

[Stu_2011]

Hi

Looks good., I did something similar to a WO focuser a while ago.. Electric focusers are the way to go.

After fiddling around a bit I realised that it's better to remove the two speed focus wheel and fit the motor on that side. The two speed wheel fixes the position of the shaft in height, if you remove the two speed wheel then the focus shaft is allowed to float and the contact with the flat region of the focus tube is greatly improved and this in turn improves focusing. Crayfords work best when the focus shaft runs perfectly true against the draw tube flat. If the shaft floats then this occurs easily, if it's held at one end (as with the two speed focus wheel) then the height adjustment is critical.

It will still works fine as you have it and once the height is adjusted its fine,. It just makes life a bit easier if it's fitted on the other side.

Thanks

Sent from my iPad using Tapatalk

[Astroboffin]

Hi

Looks good., I did something similar to a WO focuser a while ago.. Electric focusers are the way to go.

After fiddling around a bit I realised that it's better to remove the two speed focus wheel and fit the motor on that side. The two speed wheel fixes the position of the shaft in height, if you remove the two speed wheel then the focus shaft is allowed to float and the contact with the flat region of the focus tube is greatly improved and this in turn improves focusing. Crayfords work best when the focus shaft runs perfectly true against the draw tube flat. If the shaft floats then this occurs easily, if it's held at one end (as with the two speed focus wheel) then the height adjustment is critical.

It will still works fine as you have it and once the height is adjusted its fine,. It just makes life a bit easier if it's fitted on the other side.

Thanks

Sent from my iPad using Tapatalk

Hi,

Thanks for the advice

The reason I put it on the single speed side, was so if I ever want to focus manually then all I have to do is loosen the grub screw that locks the electric focuser shaft, one turn is all it news, this then disengages the electric focuser and allows me it use the manual controls.

Regards

AB

[Astroboffin]

Hi,

Thanks for the advice

The reason I put it on the single speed side, was so if I ever want to focus manually then all I have to do is loosen the grub screw that locks the electric focuser shaft, one turn is all it news, this then disengages the electric focuser and allows me it use the manual controls.

Regards

AB

Hi,

Just found out on my model scope both sides of the focuser float, if you remove the tension and locking screw the whole thing is floating, the black housing you see on the last photo on the right side is not fixed to the optical tube in any way, so with both the above mentioned screws removed it is all loose and wobbly, so I don't think it mattered which side I put it on, I know some scopes have 4 retaining screws on the focus mount, (in fact I think most do) but as you can see from the picture mine has none.

Regards

AB

[JamesF]

I've done some similar conversions myself, but mounted the motor under the the focuser and connected the two with a belt drive which meant I could make a simple clutch to allow the focuser to be used manually if required.  Wasn't my idea originally, but it seemed like a good one

James

[Gina]

Nice tidy job