DIY Auto Focuser

[Abernus]

Hi all,

Just wondering if an Auto focuser makes a difference or not. I find I get a lot of scope wobble when I try and focus in on any object. I know the EQ1 stand is a bit poo, but it's what I have to work with atm. SO would an auto focuser remove the wobble?

I used to be a sparkey so working with electronics is not a problem for me. While looking through Google I found this: Auto Focuser DIY I would be able to make this without too much effort. I don't want to spend the time and money if this will not make much of a difference in the wobble while focusing.

Thanks for any advise.

[OzDave]

I expect it will make a substantial difference. Anything you can do to avoid touching the scope will reap big rewards. This is something I've been considering doing myself.

Dave

[Abernus]

Thanks for the info. I will make a start on designing it and seeing what it will cost for parts etc. When this gets underway I will see about posting the build in progress and instructions.

I hope this will solve my current problem. THere is nothing worse than getting an item in focus and releaseing the scope, only to find out the wobble you put on it put the item in focus

[Merlin66]

Which telescope and focuser do you use?

[Demonperformer]

The article certainly makes it look easy, so I will watch your progress with interest. Maybe even someone a kak-handed as I am could give it a go ...

[Abernus]

I use an old Meade 6" reflector with the stock focuser that came with it. When I get home tonight I will post a pic to this thread. I find it a little stiff atm and fine tuning the focus is a bit of a pain.

Also while we have light nights this project might keep me out of trouble and off Astro Buy & Sell, FLO and other sites I can't afford!

[Macavity]

I did something similar(?) to the article:

http://stargazerslounge.com/diy-astronomer/103766-minimalist-motorised-focusser-mak127.html

I learned that there can be a FAIR bit of torque involved and preferred a non-slip BELT DRIVE. I sense a servo rather than conventional DC motor might have been better? At least for the prototype (usually called my production! LOL) version a simple non-locking three way DPDT switch (and potentiometer) to control motor direction / speed proved adequate, if not particularly fancy...

[Abernus]

Thanks for the info, I am going to do a lot of reasearch in to what others have done and commerical ones. If not planned out (like most of my DIY stuff) I will end up with a gear ratio that moves too fast and has a lot of slip. Will also have to work out how to attach it.

I can't wait to start this.

[Merlin66]

The "fall" back should be a SW electronic focuser motor/ controller - around 45gbp.

Check out the total costs of components and add in the pain and suffering.... I use the SW on my ED80. Works 100%

Ken

[Abernus]

Just looking on Maplin for a quick guide to prices this is what I have come up with:

Rocker switch: £2.99

Servo: £14.99

Box £1.99

phono Connectors: £2.00

Cord: £5.00

Total about £27. I am sure if I look around the house I will have some of these bits already. I am also sure I can get a servo cheaper than £15!!!

I hope to get costs down to about £20. The real pain is working out how to mount this, but thats half the fun aswell.

Thanks for the heads up on the retail one for £45, will keep this in mind

[themos]

I hope to get costs down to about £20. The real pain is working out how to mount this, but thats half the fun aswell.

I used an extra scope ring for this. You might be able to use the existing focuser as an anchor point, though.

[Earl]

here is a cheap mount which might help also

BRAND NEW CELESTRON OMNI CG-4 MOUNT XLT SERIES on eBay (end time 31-Jul-10 11:09:51 BST)

[Abernus]

oh now stop tempting me with more things to buy....

The mount will help as the EQ1 is very wobbly, at the moment I hang some old weights from the middle to try and stabilise it

[Earl]

It would be a really good upgrade and the price is good for what you get.

[Abernus]

trying to stop my hand grabbing my wallet, nnoooooooooo

[Abernus]

Here is a pic of the stock focuser on my scope.

I am thinking of attaching the motor to the 2 screws that are facing the front in this photo. Should give a good hold and wont be inthe way.

[themos]

I think the problem is that these two screws adjust the force that holds the rack and pinion together so you can't tighten them too much. I used an extra ring for the purpose, you can see it in this photo although the motor was not yet mounted on it in that pic. You can also see the improvised coupler :-)