ERIC Number: EJ755139
Record Type: Journal
Publication Date: 2006-Mar
Reference Count: 0
Measuring the Orbital Period of the Moon Using a Digital Camera
Hughes, Stephen W.
Physics Education, v41 n2 p144-150 Mar 2006
A method of measuring the orbital velocity of the Moon around the Earth using a digital camera is described. Separate images of the Moon and stars taken 24 hours apart were loaded into Microsoft PowerPoint and the centre of the Moon marked on each image. Four stars common to both images were connected together to form a "home-made" constellation. On each image the Moon and constellation were grouped together. The group from one image was pasted onto the other image and translated and rotated so that the two constellations overlay each other. The distance between the Moon centres in pixels was converted into a physical distance on the CCD chip in order to calculate the angular separation on the sky. The angular movement was then used to calculate the orbital period of the Moon. A metre rule was photographed from a known distance in order to calculate the physical size of the CCD pixels. The orbital period of the Moon was measured as 27.1 days, which is within 0.7% of the actual period of 27.3 days.
Descriptors: Astronomy, Photography, Physics, Measurement Equipment, Measurement Techniques, Mechanics (Physics), Secondary School Science, Science Instruction, Science Activities
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Publication Type: Journal Articles; Reports - Descriptive
Education Level: Secondary Education
Authoring Institution: N/A