Looks good Chris.
do you have any close ups of the mount?
I've always wanted to build one. never really understood it though.
what do you think would be the longest exposure you could get with tracking on?
have you thought of using these easy to use stepper boards that do microstepping ?
http://littlebirdelectronics.com/pro...r-motor-driver
http://littlebirdelectronics.com/pro...age-regulators
these drive motors straight. all you need is a 555 oscillator.