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Almost-full moon near star Aldebaran on December 15

The moon is not quite full on Sunday night, December 15, 2013.  The bright star nearby is Aldebaran in the constellation Taurus.

Tonight for December 15, 2013

The moon might look full to you this Sunday night – December 15, 2013 – but technically speaking, it’s still a waxing gibbous moon. Waxing means the illuminated portion of the moon’s disk is increasing; gibbous means the moon’s face is more than half-lit but less than full. You might – or might not – see the red star Aldebaran in the moon’s glare tonight. The Pleiades star cluster, also called the Seven Sisters, is also nearby. If you can’t see these objects, try binoculars.

Smallest full moon of 2013 on night of December 16-17

Aldebaran is the brightest star in the constellation Taurus the Bull. It is a reddish star and depicts the Bull’s fiery red eye. On a dark night, the ruddy color of this wonderful star really stands out in a dark, moonless sky. Be sure to check out the star Aldebaran and the starlit figure of the Bull in a week or so, after the moon has left the evening sky.

View larger. | Here is the bright planet Jupiter in the stars of the Winter Circle on December 14, 2013.  See Aldebaran in the lower right corner?  By the night of December 15, the moon will be in this picture, too ... near Aldebaran.  EarthSky Facebook friend Jv Noriega capture and composed this beautiful photo.  Visit Jv Noriega's Facebook page.

View larger. | Here is the bright planet Jupiter in the stars of the Winter Circle on December 14, 2013. See Aldebaran in the lower right corner? By the night of December 15, the moon will be in this picture, too … near Aldebaran. EarthSky Facebook friend Jv Noriega capture and composed this beautiful photo. Visit Jv Noriega’s Facebook page.

Aldebaran is a star of the Zodiac, that narrow roadway of the starry sky upon which the moon forever travels. The moon passes relatively close to Aldebaran every month. But how close the moon approaches Aldebaran in any given month depends on the moon’s shifting orbital path and its accompanying 18.6-year lunar cycle. At a certain point, the moon actually strays far enough south of the ecliptic to occult – cover over – Aldebaran during its monthly travels through Taurus the Bull.

In fact, the first of a series of lunar occultations of Aldebaran will begin on January 29, 2015, and will end on September 3, 2018. Tonight’s relatively close pairing of the moon and Aldebaran is only a prelude of much closer pairings yet to come!

constellation Taurus

When the moon is far enough north of the ecliptic, it can occult the Pleiades star cluster – or even the star Elnath. On the other hand, when the moon resides south of the ecliptic, it can occult the star Aldebaran. When the moon passes through Taurus, it can swing anywhere from 5o north to 5o south of the ecliptic, depending on where the moon is positioned in its 18.6-year cycle.

Bottom line: The bright star in the moon’s glare on Sunday evening, December 15 is Aldebaran, fiery eye of the Bull in the constellation Taurus. The Pleiades or Seven Sisters is also nearby.

Aldebaran is the Bull’s fiery eye

Taurus? Here’s your constellation