electric focuser

[sologuitarist61]

I have a Skywatcher 120 Star Travel telescope and wish to fit an electric focuser. Unfortunately the SkyWatcher electric focuser (although apparently correct for my scope) does not fit as I cannot remove the focuser turning wheel to replace it with the electric version. See these photos

Has anyone else come across this problem and found a solution please. Thanks in advance

[bluemarkus]

i built myself an electronic focusser for my dobson, but havent used it since i havent gotten into imaging so far. i built mine from LEGO and it worked great. but probably that was not the answer u were looking for

cheers MB

[Steve Ward]

It does work on ST120 , you need to remove the focuser bar and unscrew one of the wheels , mine were really tight ( Loctited in place ? ) but they will come off.

[sologuitarist61]

Cheers bluemarkus, at 65 I think people might look at me a bit strangely if I started buying Lego ..... :laugh:

[sologuitarist61]

It does work on ST120 , you need to remove the focuser bar and unscrew one of the wheels , mine were really tight ( Loctited in place ? ) but they will come off.

When you say 'unscrew one of the wheels' do you mean that there is a screw in the focuser that hold the wheel in place, or that you literally use brute force to unscrew the wheel? :confused:

[Viv]

There is a grub screw (if it's the same design as ED80), that hold the wheel.

[sologuitarist61]

There is a grub screw (if it's the same design as ED80), that hold the wheel.

Nope, no grub screw either on the front or of the back of the wheels (unless it is in the focuser mechanism which would be pointless as I would still need the bar to attach too). I am wondering if just trying to force the wheel to unscrew might do the trick but don't want to have buy a new focuser if it goes wrong!!!

[Viv]

Not even on the inside of the wheel, where it attaches to the rotating bar ?

[sologuitarist61]

'Fraid not Viv below is a picture of the inside of the wheel (both are the same) with no sign of a grub screw.

[Viv]

Let me try again.

Sorry - I'm just lost now.

Someone here must have upgraded the same as you .............

[Black Knight]

I've not seen an ST120, but surely you can uncover the rotating axle that the focus knobs attach to without removing the entire focuser? In the last picture you posted, do those 2 screws (and presumably another 2 at the other end) attach a plate of some description to the focuser? Is it possible you could post a picture of the underside of the focuser clearly showing these screws?

[sologuitarist61]

I've not seen an ST120, but surely you can uncover the rotating axle that the focus knobs attach to without removing the entire focuser? In the last picture you posted, do those 2 screws (and presumably another 2 at the other end) attach a plate of some description to the focuser? Is it possible you could post a picture of the underside of the focuser clearly showing these screws?

Thanks Andy

Yes indeed, there are in fact 4 small screws attaching a plate to the underside of the focuser - so I guess that if I remove them then I can take out the whole of the rotating shaft, but I still then need to get the wheel off somehow, which is the main problem I cannot seem to get around. Whether the actual wheels are screwed on with lock-tight, or are just gled on I have no idea.