Double Arm Barn Door Tracker

Smits notes that all of dave trott s drives including the single arm version have the drive screw mounted as the expanding base of an isosceles triangle.

Double arm barn door tracker.

First cut the 500mm length in half and mount the hinge. Double arm barn door tracker. For some of my longer exposures i use this device which can track the motion of the stars across the sky while the image is being made. The hinge is aligned with a celestial pole and the boards are then driven apart or together at a constant rate usually by turning a.

To use it the tracker is set up in the field so that the hinges are aligned with the earth s axis of rotation. Make sure everything is square and moves freely clap the 2 hinged boards together and shout action a few times like they do when making movies if it makes a nice clack sound it should work well for a star tracker now measure 228 55mm from the center of the hinge pin down the middle of the board and mark the drive rod holes do this on. His paper a mathematical analysis of the double arm barn door drive appears on pages 155 160 of the december 1988 monthly notices of the astronomical society of south africa. A simple single arm barn door tracker can be made by attaching two pieces of wood together with a hinge.

Construction plans for a star tracker. How to build a double arm barn door tracker jefferson lab home page science education home page construction notes photos page sources. Sky telescope april 1989 p436 p441 very good. Signal frequencies on cmos 4024 pins.

Sky telescope february 1988 p213 p214. A camera is mounted on the top board usually with some sort of ball joint to allow the camera to be pointed in any direction. Calculation of drive arm length. A double arm mount offers much greater accuracy than conventional designs.