Orpington Astronomical Society

Astronomy => Technical => Topic started by: Fay on Dec 04, 2012, 22:57:21

Title: Scope focusing tube slips when at zenith
Post by: Fay on Dec 04, 2012, 22:57:21
My 120 is a nightmare for the above. If the locking screw is tight then you cant focus & if it is loose, it slips while trying to focus. or if I have focus & then tighten the locking screw, it puts it out of focus again.

Has anyone a remedy, before I reach for the hammer?

Thanks
Title: Re: Scope focusing tube slips when at zenith
Post by: MarkS on Dec 04, 2012, 23:17:01
Could you focus it then tighten the locking screw to prevent slippage?  If you need to subsequently refocus then loosen the locking screw slightly.

This is exactly what I have to do on the Bananascope.
Title: Re: Scope focusing tube slips when at zenith
Post by: Fay on Dec 04, 2012, 23:23:39
Yes, i do focus then tighten the screw again, but it puts it out of focus again, as I tighten it. i think I will have a good look at it, & see if any of the other screws do anything. it seems like it is not gripping inside
Title: Re: Scope focusing tube slips when at zenith
Post by: Carole on Dec 05, 2012, 00:27:42
Oh dear, I feel for you Fay.  I used to have the same problem with my first scope the Megrez 72 it was a PITA, especially as I was a real beginner then.  Mine used to slip in any position.  I had to tighten the drawtube, but then it ended up a bit too tight and scraping, but at least it didn't slip any more.  See if there are some adjustment screws/nuts that you can tighten it up with (I don't mean the locking screw).

Carole

Title: Re: Scope focusing tube slips when at zenith
Post by: Fay on Dec 05, 2012, 08:48:51
yes I am going to do that today, Carole, & tighten everything!
Title: Re: Scope focusing tube slips when at zenith
Post by: Tony G on Dec 05, 2012, 23:14:02
Quote from: Carole on Dec 05, 2012, 00:27:42
Mine used to slip in any position. 

:o :o

Luckily that was posted after the watershed.

Tony G
Title: Re: Scope focusing tube slips when at zenith
Post by: Carole on Dec 06, 2012, 13:21:47
Oh dear.  Pampas grass again.

Carole
Title: Re: Scope focusing tube slips when at zenith
Post by: RobertM on Dec 06, 2012, 14:46:29
The scope warrants a decent focuser not the lightweight one they put on it !