Libration of the Moon

February 25, 2005


Provided by: Laurent Laveder, Optics of the Atmosphere Gallery
Summary authors & editors: Laurent Laveder

The above photo sequence showing the libration of the Moon was taken this past December from Quimper, Bretagne, France. A DC Camedia 5060 camera was used with a 25 mm eyepiece, mounted on an inexpensive 80/480 mm refractor telescope. To construct this sequence, pictures of the Moon were taken when it was between 5 to 16 days old -- from waxing crescent phase to just past full. Fortunately, the weather was clear on most every night in mid December. I used 10 images to make this animation illustrating the variations in the Moon's surface area. Daily changes of geometric perspective of an observer on the Earth's surface together with variations in the rate of the Moon's orbital motion produce librations, which permit astonomers to view more than 50% of the lunar surface during the Moon's 29 day cycle. In this animation, also note the diminution of the Moon's apparent size from the crescent to the Full Moon -- this was the most distant full Moon in 2004. Click on the image above to see the animated GIF.

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