Help !! ..... Need a new focuser.

[Craney]

Evening everybody,

A few months ago my Opticstar AR80S (f5) Gold  took a tumble whilst being used as a guider.   ( This is a manufacturer's image)

The impact was wholly on the focuser.  It didn't sound good.  It was grinding, only went one way and started to leak ball bearings.  It also has a severe wobble that suggested something is not entirely spherical or cylindrical any more.  The optics (amazingly !! )  look fine, so it's time to try to find a replacement focuser.

Peter at Opticstar is really , really helpful and I am going to send him these photo's tonight, as he said he would try to suggest a solution.  

In the mean time I was wondering if anybody here on SGL could give any advice or point me towards a unit that will fit. 

 

Here are the photo's. I have tried to give an idea of sizing with a ruler, but I aint no engineer. I separated the focuser from the White tube ( which has a black flange on the end) to give some idea of the internal dimensions.

 

Cheers in advance.

 

 

Sean.

 

[Peter Drew]

Bad luck!. Sounds like the outer race of one or more of the small focus tube support bearings has broken and released the balls. Theses bearings can be replaced fairly easily if you are unable to obtain a replacement focuser.   ?

[DRT]

I believe Opticstar re-brand telescopes made by one of the main manufacturers, I cannot remember which one (might be GSO?) but I think Rother Valley Optics use the same source for their own branded OTAs.

I'd suggest calling Opticstar or RVO and asking which brand of refractor focusers fit these scopes. From the look of the pictures you need a focuser with an 85mm dovetail fitting to attach to the black adapter fitted to your tube.

[Knighty2112]

I’d take out the dual speed axle from the focuser and check that axel is still straight, and check the four roller bearings in the upper part of the focuser mechanism. These are held in place but the block that holds them and can be fully released by just two small screws with an Allen key. Had issues with my dual speed focuser when I had my Opticastar. In the end I too out the brass fine tuning dial and small axel and just used it with the course focuser knobs. Worked much better and smoother.

[Knighty2112]

Also, check the inner focuser clutch adjustment as detailed in the user manual. There are some fine ball bearings in there that if you tighten too much can cause an issue too.

http://www.opticstar.com/Download/Astro/Doc/Telescopes/Opticstar/Opticstar-AR-Telescopes.pdf

[Knighty2112]

BTW: if the issue lies in just the rotating part of the focuser, you could tighten down the small securing grub screws that it rotates on to lock it in to place fully. 

[Craney]

Thanks for the replies guys. Sorry for the delay,I have been out under the skies trying to get my big Newt firing on all cylinders...

 

Yes, @Peter Drew there were a few Ball Bearings escaping from the end of the tube when I first investigated the damage !!!.... An immediate look at the component parts suggested that it might be best to replace the whole unit.  But the wisdom might be to have a tinker with it.

That's good info @DRT.   I was rather hoping that it would be a 'stock' focuser and possibly obtainable from FLO or RVO.... Peter from Opticstar is going to get back to me with a suggestion, he might have spares floating around.  It looks like that particular model is not available anymore.

Thanks @Knighty2112.....   I must have those instructions somewhere.  I feel you might be over estimating my technical skills, but...... if I know I can replace the back end then it is worth a bash at trying to salvage some functionality.   I think I would just use it for guiding if it were partially repaired, so to be able to achieve  pin point focus may not be totally necessary.  Thanks for the suggestions.  It sounds like you have been here before with focusers.

 

I'll report back what Opticstar have to say.

Clear skies folks...

Sean.