this is a key wround camera clock. you put clock on (your) tripod and the camera on one side ot the brass rod, set the counterweight to balance it. level your tripod, aim the polar finder at north star and take a timed photo of the object. the clock was made in germany and is very accurate. comes with two keys and a laser beam pointer. (no tripod) hole in base is 1/4-20. $350.00 U.S.only. please feel free to call me with any questions.