This Week’s Sky at a Glance, December 23 – 30 ~by Curt Nason
Having official constellations doesn’t prevent us from imagining our own. The sight of Orion, with club raised high and a lion-skin shield warding off the horns of a raging bull, has been etched in my memory for over half a century. But, come December, reddish Betelgeuse in Orion’s armpit becomes Santa’s red nose in profile, the curve of the shield outlines a sack of toys, and the iconic three-star belt is…well, that wide black leather belt. And on cold, clear nights there is no mistaking that twinkle in his eye. Look to the north and there is Santa’s sleigh, usually seen as the Big Dipper, being loaded up for the long night’s ride.
Many doors and windows are decorated with wreaths and the window of the winter sky is no exception. Here, Betelgeuse is a red light near the middle of a wreath we call the Winter Circle or Hexagon. By mid-evening you can trace the lights decorating the wreath, from blue-white Rigel in Orion’s leg to brilliant Sirius the Dog Star, up through Procyon the Little Dog Star, around Pollux and Castor in Gemini and Capella in Auriga to orange Aldebaran as the Bull’s eye, and back to Rigel.
If you prefer an even more traditional Christmas view, but one that will require binoculars, it is found in the constellation Cancer and is best seen in late evening when it is higher. A star cluster called the Beehive also goes by the name Praesepe, which is Latin for the Manger. Under a clear dark sky the cluster can just be detected as a fuzzy patch to the eye. It lies within a square of four stars, the two brightest of which are called Assellus Borealis and Assellus Australis, the northern and southern asses feeding at the manger. Can you picture Auriga and the twins of Gemini as the Magi on their eastward journey?
Imagination is a gift and Santa won’t mind if you open yours before Christmas.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 7:59 am and sunset will occur at 4:37 pm, giving 8 hours, 38 minutes of daylight (8:01 am and 4:45 pm in Saint John). Next Saturday the Sun will rise at 8:01 am and set at 4:42 pm, giving 8 hours, 41 minutes of daylight (8:03 am and 4:50 pm in Saint John). Have you noticed the Sun has been setting later over the past week but it continues to rise later each day?
The Moon is at first quarter on Tuesday, making a great target for any new telescopes and binoculars found under the Christmas tree. On December 30 it occults the bright star Aldebaran around 7:30 pm, with the star reappearing a little less than an hour later. Mars is about seven degrees to the upper right of Jupiter this weekend, and moves to within half that distance by next weekend. Mercury can be found in-line well to their lower left, rising around 6:15 am midweek. Use binoculars to locate it, and then try to see it without the binos.
Questions? Contact Curt Nason.