Ideas for upgrading focuser on small refractor

[chrisp9au (Chris)]

I would like to replace the rack & pinion focuser on my Orion ST90 with a Crayford unit that I bought a while ago.

The existing r&p unit 'wobbles' around all over the place when focusing, and my efforts to correct this have only been partially successful. I'm 100% sure that the Crayford would resolve the problem and give me much better views through this scope.

However, this means that I need to manufacture a collar or adapter to attach the focuser to the tube. My metal working skills are zero, and I don't think I'm going to find an off the shelf unit that would do the trick.

So, I either have to learn of a simple way that others have used to tackle this task, and that I could do myself, or have the unit made up for me.

I'm wondering if there is anyone in the IIS community who does small jobs like this? I would cheerfully pay for materials and labor to get the job done properly.

Cheers
Chris

[chrisp9au (Chris)]

This is an incredible website, full of great people!

I've received an offer to make up the required part, which I have accepted!

Cheers
Chris

[Kevnool (Kev)]

Yes Chris there are some truly wonderful people here.
It does make you glad.
Great write.

Cheers Kev.

[GeoffW1 (Geoff)]

Originally Posted by chrisp9au

This is an incredible website, full of great people!

Chris

Ah, so true

[GeoffW1 (Geoff)]

Originally Posted by chrisp9au

I would like to replace the rack & pinion focuser on my Orion ST90 with a Crayford unit that I bought a while ago.

The existing r&p unit 'wobbles' around all over the place when focusing, and my efforts to correct this have only been partially successful. I'm 100% sure that the Crayford would resolve the problem and give me much better views through this scope.


Chris

Hi,

Chris has a good solution, and another one may be to try an electric focuser (focusser??) in some cases.

It worked for me on a Skywatcher SW102.

Any thoughts?

Cheers

[chrisp9au (Chris)]

G'day Geoff,

I have the Crayford waiting to be put to good use, so that's the way I'll go.
Electric focuser? The KISS principle rules! My metal working skills = zero, my electriconics skills fall short of that!

Cheers
Chris

[Jfinis (Jim)]

Hi all,
Can anyone help, I'm looking for an electric focuser to fit a new William Optics Megrez 88 refractor, it has a dual speed 10:1 manual focuser
Help much appreciated
Regards
Jim

[chrisp9au (Chris)]

Due to the generosity of an IIS member my small Orion 90mm ST refractor is up and going again, upgraded to a 2" Crayford focuser and a decent diagonal, first light will be tonight!
Picture attached, plus one of the neighbors lining up for a look!

I won't identify the member because I don't want him to be inundated with similar requests! But I am very grateful for his time and effort in helping me to get even more pleasure from my gear, Thanks mate!

Cheers
Chris

[BerrieK]

Great outcome for you Chris, and a fantastic group of generous people here to boot.

Kerrie

[bojan]

Chris, this looks fantastic!

[chrisp9au (Chris)]

G'day Bojan,

Yes looks good and sees good! That $2 dew guard makes it look rather grand, but I tell you it was needed last night! The Crayford focuser, 2nd hand, makes a big difference, no play, smooth movement, and the collimation is pretty much spot on.

So, this is my 'grab 'n go' scope all set up, now I can spend my time working on my next project.
My 127mm F9.45 Surplus Shed objective arrived on Thursday!

Cheers
Chris

[rogerco (Roger)]

With regards to the secondary question on electric focuser. JMI make a push on job that goes over the fine focus knob (the smaller of the two). However the fixing for the GSO style of 10:1 focuser is not good as it is based on double sided stick tape and a separate piece of metal. It works but I am still working on mine to make it more solid. Also they are rather expensive for what you get. But in terms of getting rid of the wobbles they are great. You will never go back to using fingers on knobs again five minutes after trying an electric focuser.

Before you look into buying anything to add onto a ficuser look at how much backlash your current focuser has as this will effect how far you can go in fine tuning your focusing particularly if you are imaging, where focusing becomes many times more critical.

Roger