I posted these two barndoor mounts on Thiniverse a few days ago. One is manually operated while the other is motorized.
Manual Stars Tracker kit:
http://www.thingiverse.com/thing:11376

Motorized Stars Tracker kit:
http://www.thingiverse.com/thing:10756

Since I have not that much time on my hands, I decided to merge both projects so that I can chose between the portability of the manual version and the ease of use and accuracy of the motorized version.
The new manual version looks pretty much like it’s ancestor with some minor modifications. The length of the device has been cut in half and some minor bugs have been fixed.

I am now working at motorizing this new version of the manual Star Tracker. I want to make it simple to switch from the manual to the motorized version by reusing as much parts as possible.
I ended up today with this motor support that should replace the actual wheel of the Star Tracker.

I am using the same type of attachments as the frame of the Makerbot. This technique is pretty cheap and allows strong assemblies using plastic and wood.
Next step will be to design a coupling to attach the motor to the 1/4″ threaded rod of the tracker. I think I’ll use the same type of coupling as the Reprap 3D printer.
October 6, 2011
Awesome.