Tuesday, May 18, 2010

At dusk, a distant conjunction of Venus and the moon

There are closer conjunctions of Venus and the moon yet to come this year (see below), but I never miss a chance to photograph these two heavenly objects during a rendezvous. This time, it was just after sunset, with a deep-blue sky.

This distant conjunction came the night after a new moon, so the waxing crescent was at its skinniest (Venus, coincidentally, also was a crescent, if only I zoomed in closer). Additionally, sunlight bouncing off Earth and hitting the moon's surface faintly lit the other 97 percent of the disk that wasn't illuminated directly. The strength of this phenomenon -- called "planetshine" or "Earthshine," in our particular case -- is determined by which part of Earth is seeing daylight at the time (land reflects more than oceans) and by the amount of cloud cover in that area (clouds reflect half the light hitting them).

Of course, the best conjunction in a while happened early one morning in April 2009. See that post here. A better conjunction-viewing opportunity is coming after sunset on Aug. 13, when Mars joins the party with Venus and the moon.

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