This Week’s Sky at a Glance, 2023 Dec. 16 – Dec. 23
This Week’s Sky at a Glance, 2023 Dec. 16 – Dec. 23
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, Santa’s 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 Circlet or Winter Hexagon. By mid-evening you can trace the lights decorating the wreath, from blue-white Rigel in Orion’s leg to brilliantly colourful 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. 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 7:55 and sunset will occur at 4:34, giving 8 hours, 39 minutes of daylight (7:57 and 4:42 in Saint John). Next Saturday the Sun will rise at 7:59 and set at 4:37, giving 8 hours, 38 minutes of daylight (8:01 and 4:45 in Saint John). The Sun reaches the winter solstice, its most southerly point on the ecliptic, on Thursday at 11:27 pm.
The Moon is near Saturn this Sunday, at first quarter on Tuesday and near Jupiter on Friday. Saturn is best seen in the early evening, setting around 10 pm midweek. On Tuesday telescope users can watch Jupiter’s moon Ganymede disappear behind the planet at 7:44 and reappear at 9:27, and then disappear into Jupiter’s shadow just after midnight. Mercury becomes increasingly difficult to see, reaching inferior conjunction next Friday. Venus is slowly moving sunward but it will remain in the morning sky throughout the winter. The minor Ursid meteor shower, with its radiant near the bowl of the Little Dipper, peaks next Friday evening.
On Sunday evening at 8 pm, tune in to the Sunday Night Astronomy Show via the Facebook page or YouTube channel of Astronomy by the Bay. This will be the last live show until January 7, but you can binge previous shows on the YouTube Channel.