Theory of Operation:
The ideal system is two boards attached together by a hinge. One board is fixed and other board (the camera board) is being driven at the same rate as the Earth rotates. The pin of the hinge is pointed to a celestial pole. Tangential and Isosceles drive systems are two board systems. However, their performance is poor for long exposures.
Double Arm System: Basically, you have a three boards. A fixed base board, a drive arm board, and a camera arm board. The drive arm and camera arm boards are attached to the base board by two brass hinges. One hinge for each board. A motor rotates a threaded rod that pushes that drive arm and the base board apart. The drive arm in turns pushes the camera arm. |
