GSO 10.1 Micro-focuser slipping? Help please

Davekyn (David) · #1 08-10-2008, 09:03 PM

Hi,
Could anyone explain a way to fix a 2” Microfocuser that keeps slipping every time I move the scope from the zenith position…(that is with No EP in it as well???)

I am not having much luck with this dob.

The focuser seems to lose traction all the time now…I have tried tightening the Philips head screws around the bottom of the thing, but all that does is bur the cheap screws???

Something must of come loose, during my transporting of it, in and out of the house…any ideas what I could try as I only just bought the thing?

Thanks for any help you can provide.
Dave

erick (Eric) · #2 08-10-2008, 10:14 PM

Sounds like you don't intend to return this scope for a replacement, Dave? This is the one with the dent?

The GSO Crayford has two finger operated screws under the body - the knurled screws. The one closest the body of the telescope is a lock. When you screw that in tight, the draw tube is locked and the adjustment wheel just spins. Loosen that off - you don't really need to worry about it. Just make sure it doesn't fall out and get lost during transport. If you want, remove it entirely and put it away somewhere.

The screw closest to the eyepiece sets the force with which the drive mechanism contacts the draw tube. Too loose and the drawtube slips under its own weight. That sounds like what is happening to you. Just keep tightening it up to reach the minimum tightness at which the draw tube doesn't slip under its weight. Of course, with different weight eyepieces in the focusser, you may have to adjust this tension. The objective is not to have it too tight - puts undue pressure on the various bearings contacting the drawtube. It can also change its behaviour with temperature so you might need to adjust it as the temperature falls.

Does that solve the problem?

Davekyn (David) · #3 09-10-2008, 09:53 PM

Thanks Erick,
You've done it again.

Logieberra (Logan) · #4 09-07-2010, 01:03 PM

Can I please re-open this one?

Likewise, I have a GSO focuser. I am having issues with the fine adjustment knob. It only works if I back the tension screw right off, but this is kinda pointless - because the focuser can no longer bear any weight at these settings.

What could I be doing wrong?

The locking screw is backed right off. Check.

Regardless of how tight I turn the compression screw, the main focuser adjuster knob works (you can see both the L and R sides of the focuser spinning).

When the fine adjustment knob is not working, only the right side spins (one one that I'm turning), and the left side does nothing. When the fine adjustment is working, both the left side and right side spin...

Pls help guys

Thx

Logan.

toryglen-boy (Duncan) · #5 09-07-2010, 01:14 PM

Hi Logan

THe general concensus is that while these are fine for visual use, for imaging they could be better, and almost anyone who got one as standard, specially on the RC's, has changed it over.

but hey, thats only what i have gleaned from reading over here.

casstony · #6 09-07-2010, 02:05 PM

There is a nut inside the focuser shaft assembly that needs to have the correct tension for the focuser to work properly. The following link shows the tune up procedure but it's not working at the moment - maybe try in a day or two.

http://www.backyardvoyager.com/gsofocuser.html

multiweb (Marc) · #7 09-07-2010, 03:09 PM

There seems to be a lot of bashing around those GSO 10:1 focusers. I got them all from Newt to SCT through ED80 and they're fine for imaging, no doubt about that. They're budget focusers and don't handle heavy weight too well but they're a good build and do the job nicely.

As a rule when you image or you're in focus then you should lock the focuser with the thumbscrew and you'll be good to go. If your camera assembly is too heavy and you can't focus up then focus on the way down.

If you're still having issues with the focusing mechanism then move up to a more sturdy type.

Logieberra (Logan) · #8 09-07-2010, 04:01 PM

Thanks Marc. You hit the nail on the head

"If your camera assembly is too heavy and you can't focus up then focus on the way down."

She's a shocker for AP.

bmitchell82 (Brendan) · #9 09-07-2010, 07:59 PM

I don't think its GSO bashing at all marc, and i belive you with your shots that come out. But for the majority the focuser (not GSO) just doesn't cut the mustard.

You are right with the if it doesn't focus up, go down, but that doesn't really cut the mustard either because you don't know if you have got that critical focus untill you go past and come back onto it. So it really shoots itself in the foot. I beleive that at the end of the day, if you are really into AP, then you will just bite the bullet and get the right gear. Its all in search of perfection and that little bit more.

asimov (John) · #10 09-07-2010, 10:07 PM

On most crayfords it pays to do the modification of truly 'flattening' the flat on the drawtube with a wetstone/oilstone.