Telescope won't focus or defocus at all?

[Apollo Paul]

None of my eyepieces will focus or defocus. I dont understand what is going on.

I only bought the scope new last week. Help.

[long_arms]

What scope is it?

Dan

[long_arms]

If it is a 200p dob make sure you havent got the 2 inch adapter screwed in as well. Just the bit the eyepiece goes into, screwed directly into the focuser.

Dan

[P_Monty]

What telescope? Can you post a picture of the setup so people can check everything is in the right place?

[Steve Ward]

There's a silver thumbscrew on the focuser that locks the focus position ,

The focuser wheels will still rotate with the lock done up but the tube will not move .

[Apollo Paul]

Yes its a 8" skywatcher dob

here is a pic .

P.S Should the focuser turn forever, like it is doing?

[LukeSkywatcher]

I think the issue MAY be that the big silver screw on the underneath of the focuser is not engaging the teeth of the focuser. There is another hole next to it, if you take the screw out of the hole it is in and place it in the other hole to the left, it should engage the teeth on the focuser.

I'm not saying it will, but i've heard of this before with scopes and suggested the same thing and it seems to work.

Give it a try.

The focuser should not turn forever.

Edited February 18, 2013 by LukeSkywatcher

[Steve Ward]

Try loosening the silver screw , the one facing the camera between the two wheels , if this is locked the wheels will 'turn forever' to no effect.

[LukeSkywatcher]

Try loosening the silver screw , the one facing the camera between the two wheels , if this is locked the wheels will 'turn forever' to no effect.

That's another possible fix. I didnt think of something so simple. Not too loose though or the focuser will again just turn forever.

Edited February 18, 2013 by LukeSkywatcher

[Psychobilly]

Looks like a crayford rather than a rack and pinion... So I woukd go with Steve's suggestion...

Peter...

Sent from my GT-P7300 using Tapatalk HD

[LukeSkywatcher]

Looks like a crayford rather than a rack and pinion... So I woukd go with Steve's suggestion...

Peter...

Sent from my GT-P7300 using Tapatalk HD

I agree. it looks to me like a crayford . I just googled "crayford" and they do operate mechanically differently to rack and pinion. Essentially the same solution though.

Edited February 18, 2013 by LukeSkywatcher

[Steep]

I've had the same problem a couple of times, I sometimes forget that I've tightened the screw to keep focus and wonder why I can't adjust it again.

[Apollo Paul]

Thanks alot for your help and advise. The screw was too tight. Now the focus works. I would never have thought of this

Thanks ever so much for your help.

Paul

[LukeSkywatcher]

Thanks alot for your help and advise. The screw was too tight. Now the focus works. I would never have thought of this

Thanks ever so much for your help.

Paul

Its a common issue with focusers of any type. Glad you are sorted.

[Steve Ward]

You're welcome Paul , happy hunting . . .

[BRUN]

On 18/02/2013 at 19:06, Steve Ward said:

There's a silver thumbscrew on the focuser that locks the focus position ,

The focuser wheels will still rotate with the lock done up but the tube will not move .

Thanks !

[MKHACHFE]

On 18/02/2013 at 20:25, Steep said:

I've had the same problem a couple of times, I sometimes forget that I've tightened the screw to keep focus and wonder why I can't adjust it again.

Quoted for agreement. Same thing happened to me with my XT8 two days ago...I was scratching my head till i noticed that screw. 

 

Cheers