Sky at a Glance 2020 April 4 – 11

Although Orion and his two dogs, Canis Major and Canis Minor, are slipping into the sunset, they are not the only pooches in the night sky. The small constellation of Canes Venatici the Hunting Dogs is generally seen as a pair of stars well below the handle of the Big Dipper. They assist their master, Boötes, in chasing the celestial bears around the pole.

In one tale from mythology Boötes is Icarius, a vineyard owner who was taught the art of winemaking by Bacchus. He introduced his shepherd neighbours to his product, and when they awoke hung over the next morning they thought they had been poisoned. In retaliation they killed Icarius and threw him in a ditch. His dogs, Chara and Asterion, sensed something was wrong, and when they eventually found their master they jumped into the ditch to die with him.

The brightest star in Canes Venatici is a double star called Cor Caroli, which means the Heart of Charles. Edmond Halley coined this because it was said to have shone brightly when Charles II returned to London after his defeat by Cromwell. The other naked eye star in the constellation is Chara, from the Greek word for “joy,” and opponents of the Boston Bruins will disagree with that. Halfway between Cor Caroli and Arcturus, the brightest star in Boötes, you can see a fuzzy patch with binoculars. This is the globular star cluster M3 from Messier’s catalogue. Galaxy M94 lies just north of the midpoint between Cor Caroli and Chara; and the much-imaged Whirlpool Galaxy is within the borders of Canes Venatici, despite being near the handle of the Big Dipper.

Saturday’s sunrise in Moncton is at 6:52 am and sunset will occur at 7:52 pm, giving 13 hours of daylight (6:58 am and 7:56 pm in Saint John).  Next Saturday the Sun will rise at 6:39 am and set at 8:01 pm, giving 13 hours, 22 minutes of daylight (6:45 am and 8:05 pm in Saint John).

The Moon is full on Tuesday evening, just eight and a half hours after perigee, giving extreme tides during midweek. Venus remains within a binocular view of the Pleiades for several days. Venus makes 13 orbits of the sun in the same time it takes Earth to make eight orbits. Therefore, it makes this close pass by the Pleiades in early April every eight years. Mars puts some eastward distance between it and Saturn in the morning sky, while Jupiter edges toward Saturn. Mercury rises 35 minutes before sunrise and it is pretty much out of sight.

With astronomy meetings and outreach on hold, there are many educational astronomy websites to fill your time. One I check daily is Astronomy Picture of the Day (APOD). It gives beautiful image or a short educational video with a few lines of explanation. Heavens Above is another favourite to explore.

Questions? Contact Curt Nason.