Further Tips For Construction

Another key feature of this mount is that the distance between the center of the hinge pin and the points where the curved drive rod penetrates the two plates must be exactly 7.14 inches. This is necessary so that when the nut (attached to the large gear) is turned at 1 revolution per minute on the 10-32 drive rod, it will rotate the upper plate and camera at exactly the correct rate to match the sky's rotation.

The image above shows the drive rod penetrating the upper & lower mount plates at a 7.14-inch distance from hinge pin.

The photographer can sight along the hinge pin to align it with the celestial pole. On my setup I installed a green laser to be parallel to the pin. The laser beam is then pointed at the celestial pole via adjustments on the equatorial wedge or photo tripod to ensure that the hinge pin is polar-aligned. The image above shows the camera pointed south of the celestial equator.