clertem

Hi  m000c400,

Great work !

I am working on a similar project as yours and would be interested to know what type of NEMA 17 ones you chose (these are sold in a variety of torque / steps) ?

I can see on your photo above that the RA stepper is directly connected to the mount shaft, and I am surprised that the idle torque of the motor is enough to immobilize the mount. Is it the same for the other axis (we can't see the other side). I have tried with a couple of CNC pulleys and belt for the DECL axis but unfortunately the weight of the scope+camera was too high and the belt was skipping on the pulleys all the time...

Another thing I am interested in is how you actually fixed the motors to the mount. I've been working a lot on possible design for this and came up with little successful results... The one I have for the moment is kind of supported by the counterweight shaft using a circular bracket. 

Originally the motors I got (from the bin of our engineering building at Uni) were too fast and I had to go with a worm/gear combo of about 40:1 ratio. Tests were OK on the RA axis, but the way I've got it mounted is not great and the motor vibrates, thus worm moving slowly out of its gear. I am surprised that you have achieved a working RA tracking simply on a direct connection like this !

I just have to solve that mechanical part, because for the rest, it's pretty allright. I'm driving them by an arduino (with dual stepper driver shield).

I've posted where I am so far here : 

I've also created a 3D model of the SkyWatcher EQ3 Mount piece 

http://www.123dapp.com/project/Skywatcher%20EQ3%20Mount/3366365

Thanks for helping,

Regards

Mathieu