Moon Phase for Tuesday December 20th, 2011

The Moon phase for December 20th, 2011 is a Waning Crescent phase. This is the phase where the moon is less than 50% illuminated but has not yet reached 0% illumination (which would be a New Moon).

In this part of the moon cycle, it is getting closer and closer to the Sun as viewed from Earth and the night side of the Moon is facing earth with a decreasingly thin crescent being illuminated.

The waning (shrinking) crescement Moon will rise at around midnight, transit the meridian after sunrise, before setting after noon. This phase is best viewed 1-2 hours before sunrise and is a great time to see the features of the Moon's surface. Along the illuminated crescent you can see the craters and mountains of the moon casting long shadows.

The Waxing Gibbous phase, like all moon phases, will last for just over 7 days. The actual length will vary because of the elliptical shaped orbit of the moon. During this Waxing Gibbous phase the moon will rise in the east in the mid- to late-afternoon and will be high in the eastern sky at sunset.

Assuming it's a clear night, the Waxing Gibbous moon will then be visible through most of the night before setting just before sunrise.

Fun fact: the illuminated side of a waning crescent moon is always pointed eastwards, towards the sunrise.