In the Sky This Month

The bright yellow-orange star Capella stands about a quarter of the way up the northeastern sky at nightfall. It’s the leading light of Auriga the charioteer. Capella links with the constellation’s other major stars to form a hexagon.

Sirius, the brightest star in the night sky, rises about 9 p.m. and remains visible throughout the night. It twinkles dramatically as it climbs into view. Sirius is one of our closest stellar neighbors, at a distance of 8.6 light-years.

The Geminid meteor shower is expected to be at its best tonight. Unfortunately, though, the Moon is just a couple of days past full. Its glare will overpower all but the brightest of the “shooting stars.”

The planet Saturn is about to disappear in the evening twilight. It’s easy to spot over the next few nights, though, because it’s near Venus, the “evening star.” They are quite low in the southwest shortly after sunset.

December’s full Moon is known by several names, including Cold Moon and Moon Before Yule. It’s also known as the Long-Night Moon because the Moon is in view for a longer time than any other full Moon of the year.

Aldebaran, the eye of Taurus, the bull, stands close to the Moon at nightfall and even closer to the Moon in the wee hours of the morning. Blocking the bright Moon with your hand will help you discern the star’s orange color.

As twilight fades away, the zodiac arcs high across the southern sky. It’s a trail of constellations with one thing in common: The Sun traverses their borders, so it passes through each of those constellations during the year.

Eridanus, the river, meanders through the southern evening sky. It is one of the largest constellations, stretching almost 60 degrees from north to south. Its northern end is near Rigel, the brightest star in Orion.

Pollux, the brightest star of Gemini, rises in the east-northeast in mid-evening, below its “twin,” Castor. Pollux is almost twice as massive as the Sun. Although it’s only one-fifth of the Sun’s age, it’s already finished its “normal” lifetime.

Under dark skies, the star 51 Pegasi is just visible to the unaided eye, high in the southwest at nightfall this month. It was the first Sun-like star with a confirmed planet. The planet’s discoverers earned this year’s Nobel Prize in Physis.