As fall gives way to winter, some of the most spectacular stars and constellations in the night sky wheel into prime viewing hours. Orion, the hunter, is in view for most of the night as the month begins, and all night by December’s end. A rectangle of four bright stars outlines his body, with his three-star belt at the rectangle’s center. The belt points toward Sirius, the brightest star in the night sky. Other bright sights include the twins of Gemini, yellow-orange Capella high overhead, and the V-shaped face and orange eye of Taurus.
This Week's Stargazing Tips
December 22: Rigel
Rigel, the brightest star of Orion, the hunter, is low in the east-southeast in early evening, to the right of Orion’s Belt. It is more than 20 times as massive as the Sun, dozens of times larger, and roughly 100,000 times brighter.
December 23: Northern Cross
The stars offer a holiday decoration this evening: the Northern Cross, which is also known as Cygnus, the swan. Its brightest stars form the shape of a crucifix, which stands almost straight up from the northwestern horizon at nightfall.
December 24: Moon and Mars
Mars and the Moon stage a pretty encounter this evening. Mars looks like an orange star close to the left of the Moon. They are low in the southwest at nightfall and set a couple of hours later.
December 25: Moon, Mars, and Venus
Like bulbs on a strand of Christmas lights, three worlds line up in the southwest early this evening. The most prominent is the Moon. Mars stands below and to the right of the Moon, with dazzling Venus far to the lower right of Mars, just above the horizon.
December 26: Dog Star
The star that gives the "dog days" their name is visible for most of the night during the winter months. The star is Sirius, in Canis Major, the big dog. It’s the brightest star in the entire night sky. It rises in the southeast around 8 or 9 p.m.
December 27: Moon and Fomalhaut
The Moon stands well up in the south as darkness falls this evening, with the bright star Fomalhaut far below it. Fomalhaut represents the mouth of Piscis Austrinus, the southern fish.
December 28: Alhena
Gemini is known for its two brightest stars, Pollux and Castor. They are low in the northeast in early evening, with Castor a bit above its “twin.” The constellation’s third-brightest star, Alhena, is at the bottom of the figure that outlines the twins.
Check last week's tips if you missed a day.