Crescent Moon, Venus and Twilight Sky
May 10, 2007
A day or two after the Moon has completed its “new phase,” is the best time to look for a thin, waxing crescent near the western horizon, just after sunset. You should be able to observe both a sliver of moonlight hanging in the twilight sky and a phenomenon called “earthshine.” The photo above showing a two-day-old Moon was taken about an hour after sunset from near Peterborough, Ontario on January 20, 2007. The ashen glow of earthshine (faint glow of the non sunlit portion of the Moon) is a result of sunlight being reflected off the Earth's surface and atmosphere (clouds). It was Leonardo da Vinci in the 1500s who first explained earthshine.
The bright star-like object to the lower right is actually the planet Venus. Next to the Moon, Venus is usually the brightest object in the night sky. The conjunction of a bright planet and our lone natural satellite is particularly striking when the Moon's in a crescent phase -- “the old Moon is in the new Moon’s arms.”
Be sure to look for the beautiful conjunction of the Moon and Venus on May 20.