This Week’s Sky at a Glance, March 11 – March 18 ~by Curt Nason
Two of the largest constellations are seen in the southwest and southeast around mid-evening. Eridanus the River flows from Rigel in Orion’s foot to the lower right, and then makes a sharp curve to the left before disappearing below the horizon. It doesn’t end there; it extends at least the same distance southward to terminate at Achernar, the ninth brightest star in the sky. Achernar, of course, means “the river’s end.” The star near Rigel is named Cursa, which means “the footstool.” In terms of square degrees of sky, Eridanus is the sixth largest constellation. It has been associated with many earthly rivers but most often with the Po River in Italy, which the Greeks called Eridanos.
Hydra the female Water Snake rises out of the southeast, with its head reaching as high as Orion’s. A smaller constellation called Hydrus the male Water Snake is near Achernar and is never seen from New Brunswick. Hydra is the largest of the 88 constellations and one of the longest. If you consider the horizon as the ocean surface, and if you have all night, you can picture Hydra leaping completely out of the water and disappearing in a giant belly flop. Its brightest star, Alphard the “solitary one,” just makes the top 50 in terms of brightness. In mythology the Hydra was a multi-headed creature slain by Hercules as his second labour.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 6:39 am and sunset will occur at 6:19 pm, giving 11 hours, 40 minutes of daylight (6:43 am and 6:25 pm in Saint John). Next Saturday the Sun will rise at 7:25 am and set at 7:29 pm, giving 12 hours, 4 minutes of daylight (7:30 am and 7:34 pm in Saint John). As you may have noticed, we switch to Daylight Time at 2 am this Sunday. Being slightly farther north, Moncton residents can boast of longer days than Saint John for the next six months, but Saint John stargazers will just smile throughout the slightly longer nights.
The Moon is full on Sunday, pretty to look at but a temporary nuisance for those hoping to spot a few comets in a telescope. It will be near Jupiter in our sky on Tuesday evening. This Saturday, Mercury sets 20 minutes after sunset and is nearly 20 degrees below Venus. Next Saturday, Mercury sets an hour after sunset with Venus 8 degrees to its right and a tad higher. Mars resembles an orange star much higher in the west. Saturn lies within a binocular field to the upper right of the hazy Lagoon Nebula in the southern sky before dawn. Starting mid-week, 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? Contact Curt Nason.