Measuring the Moon's orbit using a hand-held camera

This paper describes a way to measure the Moon's distance and orbital eccentricity using a digital camera. The method consists of taking photographs of the Moon and measuring the size of the lunar disk in each picture. On a series of images taken on the same night, the effect of the Earth's size is evident and thus the distance to the Moon can be computed. A larger series of images, covering several weeks, demonstrates that the Moon's orbit is not perfectly circular. (C) 2014 American Association of Physics Teachers.