The Sky This Week, 2014 January 7 - 14
|Jupiter, with Io and its shadow in transit
Imaged 2014 January 5, 03:42 UT
The Moon waxes to her full phase this week, shining down from a high perch among the stars of the Great Winter Circle. First Quarter occurs on the 7th at 10:39 pm Eastern Standard Time, with Full Moon falling on the 15th at 11:52 pm. January's Full Moon is popularly known as the Moon After Yule, the Old Moon, or the Wolf Moon. I particularly like the latter name as it conjures images of wolf packs patrolling the frozen ground by its pale light reflected off the snow. Look for Luna near the Pleiades star cluster on the evenings of the 10th and 11th. On the 11 she is also just four degrees northwest of the bright star Aldebaran in the constellation of Taurus, the Bull. On the 14th she's five degrees south of bright Jupiter.
The brightening Moon will once again begin to wash out the fainter stars as she waxes toward the full phase, but this month in particular she gets some pretty stiff competition from several of the night's brightest stars. It's very hard for her to overcome the stars that outline the figure of Orion, the Hunter, and the other bright stars that surround him. If you draw an imaginary line through Orion's belt stars and extend it to the southeast, you'll run into the night's brightest star, Sirius. Although the literal translation of the name means "The Scorcher", this star is popularly known as The Dog Star due to its location in the constellation of Canis Major, the Greater Dog. If you imagine Sirius as a jewel in a dog's collar, you can more or less trace out the figure of a faithful canid leaping up at the heels of his master, Orion. From Sirius, sweep your gaze to the northeast to find a more solitary star, Procyon, brightest star in Canis Minor, the Little Dog. Continue upward from here to spot the Gemini Twins, Castor and Pollux. Gemini is currently hosting the planet Jupiter, who overshadows all of his stellar neighbors. Now turn your view to the northwest of the Twin Stars and look for the bright golden glow of Capella, the lead star in the constellation of Auriga, the Charioteer. This star is actually a "quadruple" system, with two red dwarf stars orbiting a more massive pair of yellow giants. The yellow stars were the first pair to be resolved using a technique called "interferometry". Heading southwest from Capella, we encounter Aldebaran, a rose-tinted star that marks the right "eye" of Taurus, the Bull. Aldebaran appears to be a member of a large V-shaped group of stars called the Hyades, but in reality it lies at about half the distance to this cluster. Finally, sweeping southeast from Aldebaran, we land on Rigel, the brightest (usually) star in Orion. Collectively these stars are known as the Great Winter Circle, and within their bounds you'll find nine of the 25 brightest stars in the sky.
Remember Venus? Just a week ago I was looking at her from a nice location on Virginia's Northern Neck, shining like a beacon in the southwestern sky. This week she passes between the Earth and the Sun on the 11th and enters the morning sky. If you want to catch a glimpse of her you'll now need to rise before the Sun.
Jupiter, just past opposition, rises at sunset and stays in the sky all night. He is now in the prime of the current apparition, and beckons us to investigate. It was 404 years ago on the 7th that Galileo first wrote of his discovery of three of the planet's large moons (he found the fourth a few weeks later). Today almost any optical instrument will show these worlds, and many of today's amateur telescopes will reveal much more. Brave the cold weather to sight on the solar system's largest planet; he is always putting on a show!
Mars and Saturn are best seen in the morning skies, with Mars crossing the meridian at around 6:00 am and Saturn about halfway between Mars and the southeast horizon. Both planets will be well-positioned for viewing once Jupiter has run his course in the late spring.