Crayford Focusers and GSO

pmrid (Peter) · #1 10-09-2009, 09:50 AM

I'm having a 'focuser' episode.
First it was the GSO RC. Despite being hyped as the ideal scope for imagers, the focuser (a GSO Crayford-style with 10:1) was so poor that it could not take the weight of any decent sort of camera without slumping out of focus and collimation. So in order to make the RC fir for imaging, it is necessary (on the original models at least) to spend several hundred dollars more on a focuser that an imager can actually use. Let's not talk about the need to also fpock the baffle tube for much the same reason. So about A$500 and one Feather Touch later, the scope is now approaching the original hype.
Then, having sorted that out, I turn to the Newtonian on the pier beside the RC. Having recently bought a Celestron Radial Guider (A.K.A. Off-Axis Guider) that pinches about 50mm of back-focus, I decided to mount the brand spanking new Low-Profile focuser I had bought on spec some months back. Once installed, it became apparent that it was even more unstable than the one on the RC. Opening up the beast, it was apparent that the plastic track in which the axis of the focuser runs was missing. So I scavenged the one out of the 'full-length' focuser (also GSO) I had just removed. And here was that sense of dejaa vu all over again. Even with the missing bits installed, the thing could not be made to rack in and out with the weight of a DSLR on it, if you tightened the tensioninig nut enough to take out the slop. And if you applied the brakeing tension nut, the focuser tube was thrown waaay out of alignment entirely.

I am not as forgiving of the RC as others in parallel threads seem to be. If a scope is hyped as the imager's dream machine but needs another 25% of its cost price spent on a replacement this or that, I count that as a gross deficit. Now, at great expense to the management, I have compensated for the deficiencies (over-hype perhaps) of the RC but am I really going to have to go down that same road to deal with the inadequacies of the GSO focuser on my GSO Newtonian. If, as I suspect, the answer is 'yes', may I ask others whjrether there is an optio n not quite so hurtful to the budget. How do WO focusers stand up, for example, in their ability to take the weight of imaging gear?

Any recommendations?

Peter

jjjnettie (Jeanette) · #2 10-09-2009, 10:00 AM

I feel the same about my Black Diamond Peter. If a scope is touted as ideal for imaging, you should be able to use it straight out of the box.

toryglen-boy (Duncan) · #3 10-09-2009, 10:33 AM

i have seen some GSO focusers, and i wasnt a fan of them. Although the crayford that come on the Skywatcher, i find to be excellent, smooth and stable, although they could use a 10:1 focuser on them, but i will replace it at some point.

koputai (Jason) · #4 10-09-2009, 10:50 AM

I think it really comes down to 'you gets what you pays for'.
GSO stuff is ok for general plonking down and using at a beginners level or one step up from that. It's a bit like Bunnings. You go there knowing you'll be paying less, but getting lesser quality carp that's going to frustrate you.

Cheers,
Jason.

multiweb (Marc) · #5 10-09-2009, 12:41 PM

Quote:

Originally Posted by koputai

I think it really comes down to 'you gets what you pays for'.
GSO stuff is ok for general plonking down and using at a beginners level or one step up from that. It's a bit like Bunnings. You go there knowing you'll be paying less, but getting lesser quality carp that's going to frustrate you.

Cheers,
Jason.

Hey!! I've got all GSO gear!

and I'm not frustrated... yet ..

Actually I did change my WO focuser to a GSO on my C11.

bmitchell82 (Brendan) · #6 10-09-2009, 03:08 PM

The GSO/Bintel equivalent focuser 10:1 or not is definately not for imaging... in no way has it ever worked in my neck of the woods.

Recently i have done a bit of work to the SW Crayford style focuser and let me tell you that it can pull ~4kgs vertical weight and hold it. All up my work to it has equated to 0 dollars spent though im in the process of sourcing correct motors to finish the job and make it a fully electronic focusing unit (one that i would love to hook up to DSLR focuser though usb...) and ultimately making a very viable quality unit! other wise do not spend <300 on a focuser, it will not be worth the money in the long run.

wavelandscott (Scott) · #7 10-09-2009, 10:27 PM

Quote:

Originally Posted by pmrid

If, as I suspect, the answer is 'yes', may I ask others whjrether there is an optio n not quite so hurtful to the budget. How do WO focusers stand up, for example, in their ability to take the weight of imaging gear?

Any recommendations?

Peter

I'd rank the Feathertouch and then the Moonlight (great customer service) on the 'Top Shelf"...but I feel that the Feathertouch wins between the two.

Next would be the JMI and then a gap to the GSO and similar.

I've not tried the WO myself...

I own 2 Feathertouch and 2 Moonlights and haved owned JMI and GSO at diffrent times...Reflector and Refractor experience only.

multiweb (Marc) · #8 10-09-2009, 11:20 PM

Quote:

Originally Posted by bmitchell82

The GSO/Bintel equivalent focuser 10:1 or not is definately not for imaging... in no way has it ever worked in my neck of the woods.

Errr... use them all the time. C11, ED80 & C5. Got no problems. Unless your camera's 4kg but it will do for most DSLR and Cooled CCD.

Tandum (Robin) · #9 10-09-2009, 11:27 PM

http://www.iceinspace.com.au/forum/s...ad.php?t=32728

Obviously I've been looking for an answer to your question for over a year and have never seen one.

pmrid (Peter) · #10 11-09-2009, 03:07 AM

Thanks for the link Rob. Seems the problem is not new. I went back last night and had a further play after I read your thread from 2008. I saw that when the focuser worked normally, and after focus was achieved, if you tightened down the locking not it not only threw the focuser tube well out of alignment but also, and interestingly, it actually drew the tube inwards and hence out of focus again. How odd. There must be some spur on te end of the locking screw that acts like the tip of a flat screwdriver and pulls the tube forward.
But in terms of the answer, I have seen that putting a focusing motor with their inbuilt gearing, tends to hold a focuser in position pretty well, but then, a JMI or similar motor will set you back about A$250 anyway - money better spent on a focuser that won't flog around all over the place.
Peter

CoombellKid · #11 11-09-2009, 06:43 AM

I had a GSO 1:10 low profile on my dob. They cant handle heavy loads.
I couldn't even get the fine tuner to move the draw tube when my 31mm
t5 was in it. So I dumped it and got a Feathertouch... puuuuuuurfect!

problem no more.

Cheers,CS

pmrid (Peter) · #12 11-09-2009, 09:23 AM

Thanks Scott (FT and Moonlight user). I decided to have a run at a Moonlight model. I like their shaft-lock option that gets away from the Crayford tendency to shift the drawtube out of alignment.
Thanks for your input.
Peter

wavelandscott (Scott) · #13 11-09-2009, 10:21 AM

Quote:

Originally Posted by pmrid

Thanks Scott (FT and Moonlight user). I decided to have a run at a Moonlight model. I like their shaft-lock option that gets away from the Crayford tendency to shift the drawtube out of alignment.
Thanks for your input.
Peter

Good Luck and make sure you get a "cool" matching color!

I don't know if anyone is acting as a distributor for them in Australia now or not...I always dealt with Ron directly via phone and e-mail and had nothing but good service from him.

pmrid (Peter) · #14 11-09-2009, 10:37 AM

Quote:

Originally Posted by wavelandscott

.. make sure you get a "cool" matching color!

Flaming red - goes with everything.
P.

gbeal · #15 11-09-2009, 10:59 AM

And let me add Ron is absolutely awesome to deal with.

garymck (Gary) · #16 12-09-2009, 10:58 AM

Hi
Like to add my reply re Moonlight's service, which I rate as outstanding. I had a red single speed Moonlight focuser. After I had had it for about 18 months I noticed that there was some roughness in the action which turned out to be caused by patches of anodised surface that had come off the drew tube. I emailed Moonlight to ask the cost of a replacement tube, within an hour I had a reply from Ron asking why I needed a new tube. So I did a quick pick and emailed it to him an explained that I loved the focuser and new it was out of warranty and I wasn't sure what had caused the flaking so I was happy to pay for a new tube. Sent this off, in another hour had a reply saying that Moonlights have a lifetime warranty, that my pic showed it was probably faulty anodizing that was the problem, that they were going to send me a new one free of charge (including express freight) and that they would upgrade me to a compression ring type for my inconvenience! It arrived 4 days later. No wonder they have such a great reputation. We all tend to be quick at criticising, but sometimes it's nice to pass on news of fabulous service as well.....

cheers
Gary