Crescent Moon, Earthshine and Venus

June 22, 2004


Provided and copyright by: Laurent Laveder, Optics of the Atmosphere Gallery
Summary authors & editors: Jim Foster; Laurent Laveder

The above photo showing the crescent Moon and Venus was taken from Quimper, Brittany, France, on the evening of May 21, 2004. On this fine spring evening, the twilight sky displayed a gradient from deep blue to burnt orange. In addition, Venus and the Moon reclined together (just 3 degrees apart) above the western horizon. Earthshine is clearly evident on the non illuminated portion of the Moon -- this is sunlight reflected from the Earth.

The brightness of earthshine depends on the Earth’s total reflectance or albedo. The Earth’s albedo is principally governed by clouds, and during the winter season, snow cover. Thus, changes in the brightness of earthshine mainly result from changes in cloudiness. A cloudier Earth means brighter earthshine.

Note, Venus is now a "morning star," visible before dawn.

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