making my own electric focusser

[chemtom24]

just wondering how people make their own electric focusser? ive seen a thread about a servo motor somewhere but i cant find it, but that looks the easiest to me - manually controlling from a distance to eliminate shake etc.

what would i need for this?

thanks,

tom

[Stargazer Jack]

I would be interested in this as well. Also can it be done with any telescope? Thanks

[Bizibilder]

You'll find a PM on its way and this thread:

http://stargazerslounge.com/diy-astronomer/130839-fiddling-autofocusser.html

has some additional info as to how I made mine.

[chemtom24]

thanks bizi, replied. the thread I saw had somehtign liek 2 servo motors connected together, with one end attached to the focuser, so when you manually turned one motor, the other one automatically moved and turned the focuser with it.

anyone heard of anythign liek that?

[Bizibilder]

Ah! that one!! Its dead simple you just convert two servo's to continuous rotation (see item sent) and connect them with a flexible wire. As you turn the one in your hand it makes enough power to make the other (attached to the scope) turn as well. Never made one and I don't know how well it works.

[chemtom24]

thanks between this thread and my electronic engineer mate (handy being at uni!!!) i think il get there will post again with update.

and yes stargazer jack, will work with any telescope.

[Gina]

thanks bizi, replied. the thread I saw had somehtign liek 2 servo motors connected together, with one end attached to the focuser, so when you manually turned one motor, the other one automatically moved and turned the focuser with it.

anyone heard of anythign liek that?

That sounds just the thing. I have heard of such things - many years ago. I think they were powered by 400Hz power. I know how they work but not where you might get the hardware.

I'm thinking of trying a small low voltage DC motor and gearbox to drive the focuser, when I get around to it. The sort of motor/gearbox sold by Maplin. But that's probably months off. I have an observatory to build before then, as well as work on the house (window frames, painting etc.)

[Psychobilly]

Here you go chaps and chapesses...

Battery Free Electric Focuser

They want to be cheap "analog" servos rather than the more expensive "Digital" ones...

Peter...

[chemtom24]

AHA thats the one peter!

my mate has given me a parts list for an electric switched motor, gonna give that one a bash, only costing 4 quid including delivery!

if it works il post a thread about it

thanks everyone

tom

[Stargazer Jack]

Thanks for the help, will have a look and maybe build one

[Bizibilder]

I've just found the servo's for the "two servo" model here:

Hitec HS-311 Standard Servo - HS311 - £8.99

Only £18 for the two! (I've never dealt with this company but they have been around for many years).

[Starjumper]

Hi Chemtom24,

You might find some useful info on here:-

sgl_observatory_automation : SGL Observatory Automation

John

[nightfisher]

am i right thinking if you do the servo mod and mount it you can go full rack in/out by turning the donor servo, if so im thinking micro hands free focuser for my mak

[Psychobilly]

am i right thinking if you do the servo mod and mount it you can go full rack in/out by turning the donor servo, if so im thinking micro hands free focuser for my mak

Yep that's about it...

[nightfisher]

right, this sounds like a really do able idea i like it a lot

[Gina]

Hi Chemtom24,

You might find some useful info on here:-

sgl_observatory_automation : SGL Observatory Automation

John

Thanks for the link

[nightfisher]

well i have decided to use the servo focus idea for my omc140 mak,have ordered a pair of suitable servo`s but need to find a pair of small plastic pulleys, about 18mm diameter