Hi Phil many Moons ago I made a tracking device on the theory of a curved bolt arrangement, I have actually made two,over the years however this last one is the SS Model with vast improvements, maybe this sort of thing may suit you.
It is pretty simple to build, and works on a I rev/per minute motor with a small gear that rotates along a curved bolt of the correct size, and with the correct threads/pitch to the inch.
The curved bolt is than placed at the right distance to the center of the polar shaft, anyway I have the formula to construct this if you would like to have a go.
The formula is....R = 1,436.5 x (n/2<t), where this little think
< is supposed to mean
pie. in the mathamatical term, but I don't have that symbol on my keyboard.
You then just appy this formula to whatever size motor you get and thread size.
Leon
