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Thanks for the comments everyone!
The mount was just made from spare parts I had laying around. The tripod head is mounted on a camera macro focusing mount (basically a rack an pinion camera mount) so that I can adjust the balance. I used an old bicycle bottom bracket as the bearing for the mount. Both belts have tensioning systems in them. The smaller yellow one has it built into the gear assembly on the right & the brown belt can be tensioned by adjusting the angle of the cross piece.
Correct rcheshire! The steppers motor is driven by an arduino with a motor shield on it from another project which hasn't seen any work for a while. It just has a very simple program of stepping the motor every 450milliseconds. I worked out the delay time by seeing how long it took to do a quarter rotation with 1 millisecond delay then doing some simple math.
I've been out making the most of the clear skies in Melbourne for the last few nights. Below are some more photos taken from my balcony in Melbourne. First is 60x30sec of NCG6231 & M7. And second is 14x30sec the Lagoon & Triffed nebulas in the comer and M22 & M28 to the right.
I'm not happy with the design and a have a few modifications planned. The belt drives are too unreliable & make seating up very fiddily. And it is very hard to point it where you want in the sky! The tripod head is too big & can't point at certain points in the sky, and it's very hard to see stars through the camera finder. So I'm planning to ditch the belts and hook the stepper's gear train directly to the RA shaft via a 340tooth gear that I've sent off to get 3D printed. So far my thoughts are to mount the camera on a counterweight bar & mount a finder scope with the counterweight.
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