This week’s sky at a glance with a special Christmas flavour
is provided courtesy of Curt Nason.
‘Twas the week before Christmas and throughout the sky,
The stars were all twinkling their tricks on my eye.
Shapes were shifting in Urania’s vestibule,
From legends of Greece to symbols of Yule.
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 and I am ten years old whenever I see it. 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 northeast 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 light near the middle of a wreath we call the Winter Circle, or the Winter Hexagon if you are the angular type. 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 in 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, or M44 by astronomers, 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 Gemini, Auriga and Orion 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 7:57 am and sunset will occur at 4:35 pm, giving 8 hours, 38 minutes of daylight (7:59 am and 4:43 pm in Saint John). Next Saturday the Sun will rise at 8:00 am and set at 4:39 pm, giving 8 hours, 39 minutes of daylight (8:02 am and 4:47 pm in Saint John). Enjoy that extra minute of daylight next weekend. The Sun reaches its furthest point south, over the Tropic of Capricorn, at 12:48 am Tuesday, so raise a glass to the solstice if you are still up.
The Moon waxes to full at 7:11 Christmas morning, as many Facebookers know already. (That 11:11 in the Facebook message is in Universal Time, or GMT.) Full Moons occur every 29.53 days on average, and the cycle of a full Moon occurring on a particular calendar day usually repeats every 19 years, depending on the number of leap days in that interval. The full Moon near winter solstice, called the Long Night’s Moon, passes high overhead, mimicking the Sun’s path in late June.
Mercury sets a little more than an hour after sunset this weekend and stretches that to nearly an hour and a half next weekend. Jupiter rises before midnight and is at its best for observing around 6 am. Venus continues to dominate the morning twilight while Mars slides past Spica this week. Saturn now rises before 6:30 and is on a near-collision course with Venus, which will play out over the next few weeks.
Questions? Contact me at nasonc@nbnet.nb.ca
