Hi Chris, I think I know what you mean but I looked at the two mounts and one of them could be turned in a circle on a shaft perpendicular to the ground and on it it had another shaft that allowed the instrument toi be pointed up or down. The other one had a way to aim the shaft at the Pole star and then had a way to rotate a mount about that axis plus it had the capability of aiming the mount at most other points along that shaft. So three possibilities of "turning". The simple two-axis device is perfect at the poles, no? At the equator it would be clamped to a table so the major axis is parallel to the ground. teaching welcome! :) Andy
