This Week’s Sky at a Glance, March 18 – March 25 ~by Curt Nason
This week we will take the path less travelled to pick out a few of the more obscure constellations in our sky. If you don’t have a clear view to the south or if you are cursed by light pollution in that direction, they will be obscure to the point of invisible. Around 9 pm, cast your eyes toward Sirius in Canis Major, the Big Dog. If you can’t see that star, the brightest in the sky, then go back inside and read a book.
Hugging the horizon below Sirius you might detect a Y-shaped group of stars that forms Columba the Dove. This is one of the later constellations, created a century after Christopher Columbus made his first voyage, and it was meant to depict a dove sent by another famous sailor called Noah. It could also be the dove released by yet another famous sailor, Jason of the Argonauts fame, to gauge the speed of the Clashing Rocks of the Symplegades. The dove lost some tail feathers, and the Argo lost a bit of its stern.
There is a good case to be made for this interpretation. To the left of Columba, rising past the rear end of Canis Major, is the upper part of Puppis the Stern. It was once part of a much larger constellation called Argo Navis, Jason’s ship, which has been disassembled to form Puppis, Vela the Sails and Carina the Keel. Puppis is more traditionally described as the Poop Deck, a rather appropriate name considering its location relative to the Big Dog. To the left of Puppis is a vertical line of three stars forming Pyxis the (Mariner’s) Compass. At its highest it does point roughly north-south.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 7:25 am and sunset will occur at 7:29 pm, giving 12 hours, 4 minutes of daylight (7:30 am and 7:34 pm in Saint John). Next Saturday the Sun will rise at 7:12 am and set at 7:38 pm, giving 12 hours, 26 minutes of daylight (7:17 am and 7:43 pm in Saint John). On Monday at 6:29 am the Sun crosses the equator heading northward, marking the beginning of spring. Any remaining snow will magically turn to mud at that moment and marble season will officially open.
The Moon is at third quarter near Saturn on Monday, so have a look before you watch the Sun rise due east. After the Sun sets early this week, use binoculars to look for the slim crescent of Venus above it. An ambitious and careful observer might also catch it in the east before sunrise. Venus is at inferior conjunction on March 25 and becomes the Morning Star in early April. This Saturday, Mercury sets an hour after sunset with Venus 8 degrees to its right and a tad higher. Jupiter rises at 9 pm mid-week, about two hours before Mars sets. Keen eyed observers might catch the glow of the zodiacal light along the western ecliptic, in a dark sky untarnished by light pollution, about an hour after sunset.
The provincial astronomy club, RASC NB, meets at Moncton High School on Saturday, March 18 at 1 pm. One of the speakers will be a recently retired NASA astronomer and club member who was involved in building the Hubble Space Telescope. All are welcome.
Questions? You can contact Curt Nason here.