Orpington Astronomical Society

Astronomy => Technical => Topic started by: mickw on Dec 06, 2010, 11:06:57

Title: Rotating focuser
Post by: mickw on Dec 06, 2010, 11:06:57
I've just dismembered dismantled the focuser off the Burgess and sent it to IK for a fitting re: the Lakeside focuser.

There is a collar attached to the tube and 3 grub screws lock the focuser to it, the screws locate in a groove around the focuser.

If the screws are loose, the focuser rotates.
If I replaced the grub screws with knurled screws (they look to be 3mm), would I effectively have a rotating focuser - Or am I getting into the realms of doing something really bad  :-?
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 06, 2010, 12:26:24
Hi,

It will work, but check to see if the screws go into a grove or just a flange, if its the latter the focuser could fall off if you do not do the screws up properly.

Chris


P.S. Just got my stepper motor for my electronic focuser, doing it all myself, non ascom but a total cost of £ 62.00
Title: Re: Rotating focuser
Post by: mickw on Dec 06, 2010, 13:14:32
Hmmm

I think it might be safer to pass on that idea, I'll have an experiment when it all comes back.

Pity about your steppers being non Ascom, but I seem to remember someone selling a controller board for USB, so you could make it Ascom.
I'll see if I can find out who sells it - Mike should know, or even have something that would do the trick.
Title: Re: Rotating focuser
Post by: Mike on Dec 06, 2010, 13:16:06
I'll have to have a read of the Ascom spec.
Title: Re: Rotating focuser
Post by: Mac on Dec 06, 2010, 16:46:16
There is a Yahoo group for the Ascom standard.
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 06, 2010, 17:34:41
The specs and libraries are all on ASCOM the website.
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 06, 2010, 17:36:12
I would not bother Mike its .Net and I know how much you hate Microsoft, even if most of the world works on it.

Even worse it says MEADE in there a lot as well!
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 06, 2010, 17:52:52
Mac,

Just had a look there are .Net driver templated for ASCOM when you install the developer kit.

Chris
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 06, 2010, 18:28:29
Mac,

Had a further look, ASCOM builds a project template for the focuser, there is an object focus and a number of methods

       public int Position
       {
           // TODO Replace this with your implementation
           get { throw new PropertyNotImplementedException("Position", false); }
       }

       public void SetupDialog()
       {
           SetupDialogForm F = new SetupDialogForm();
           F.ShowDialog();
       }

       public double StepSize
       {
           // TODO Replace this with your implementation
           get { throw new PropertyNotImplementedException("StepSize", false); }
       }


Looks like you replace the methods with your own code, for example for the method Focuser.Halt, as below

        public void Halt()
        {
            // TODO Replace this with your implementation
            throw new MethodNotImplementedException("Halt");
        }


I guess this would morph into

        public void Halt()
        {
            // TODO Replace this with your implementation
            StopMotor(1);  //StopMoto with the parameter 1 is how I have explicitely defined one of the outputs
        }

Cool eh!

Need to get my head around it a little more bit it looks manageable but as usual I need to check some stuff with ASCOM.

Chris
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 06, 2010, 20:55:09
Yippeee, have it all compiling in C# Express now!!!

Now unfortunately I have to wait for the stepper controller now before I can continue.

DAM!
Title: Re: Rotating focuser
Post by: MarkS on Dec 07, 2010, 05:33:08
Good luck Chris - it looks like a very interesting project.

How will you interface between the PC and the motor itself?

Mark
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 08, 2010, 13:20:33
Hi,

I have a StepperBee.

Chris
Title: Re: Rotating focuser
Post by: mickw on Dec 08, 2010, 14:43:45
So you'll soon have an Ascom compliant focuser for less than £100 - cool  8)
Title: Re: Rotating focuser
Post by: Mac on Dec 08, 2010, 15:35:11
QuoteSo you'll soon have an Ascom compliant focuser for less than £100 - cool

What you really mean to say is he will have an ascom driver to operate a focuser and a focuser for less then £100 ;)

Mac.

I'll be starting my projects in the new year, now the garage is empty (and all my electronics are now unpacked and set up).

PSU, Oscilloscope, Breadboard, ect.
Title: Re: Rotating focuser
Post by: mickw on Dec 08, 2010, 16:20:59
Stoppit Mac

Otherwise I'll grass you up for having thinly disguised hide, posing as an observatory.

Put me down for 5 kilos of venison please mate  ;)
Title: Re: Rotating focuser
Post by: Rocket Pooch on Dec 08, 2010, 19:50:19
Quote from: mickw on Dec 08, 2010, 14:43:45
So you'll soon have an Ascom compliant focuser for less than £100 - cool  8)

In theory yes I guess....

The stepper bee was £32
The stepper motor was £17
A USB cable 50p
A 12v lead £2
A box and screws etc £4.50

£56 in total, the manual control is a little C# Application this was really easy, the ASCOM one I'll complete after I have played with the origional setup.

Chris