This Week’s Sky at a Glance, 2019 April 27 – May 4 ~by Curt Nason
A favourite galaxy among stargazers is M104; better known as the Sombrero Galaxy as it resembles such a bonnet in astrophotos, thanks to a central dust cloud that forms the brim. The dust cloud can be seen from a rural location with a medium-size amateur telescope. The galaxy is seen as a small gray smudge with binoculars.
Although M104 is officially within the borders of the constellation Virgo, most people start their search from the recognizable quadrilateral of stars that forms Corvus the Crow. In mythology, Corvus was sent by Apollo to fetch a cup of water from the river but the bird was distracted by ripening figs. When the crow returned late it made up a tale that it had been deterred by a water snake (Hydra). In a fit of rage, Apollo tossed the bird, the cup and the snake into the sky. To the right of Corvus is the constellation Crater the Cup, and they both sit atop Hydra. They can be seen in the southern sky when twilight fades to darkness.
To find M104, imagine a line from the middle of the bottom of Corvus to the upper left star, and extend it not quite that distance. Look in this area for a small arrowhead of three or four stars. This asterism has been called the Stargate. The arrowhead points to a small line of a few stars, which in turn points toward M104 nearby. That line of stars also forms the mouth of an asterism called the Shark, which has a fin and a curved body stretching away from the Stargate. Good luck, and wear your Sombrero proudly.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 6:12 am and sunset will occur at 8:21 pm, giving 14 hours, 9 minutes of daylight (6:19 am and 8:27 pm in Saint John). Next Saturday the Sun will rise at 6:01 am and set at 8:31 pm, giving 14 hours, 30 minutes of daylight (6:08 am and 8:33 pm in Saint John).
The Moon is at third quarter on April 26 and new on May 4. On Thursday and Friday it is near Venus and Mercury, respectively, in morning twilight. Jupiter and Saturn garner morning attention by framing the Teapot asterism of Sagittarius to the south, and on Thursday Saturn begins five months of westerly retrograde motion relative to the stars. Over the next two weeks Mars will be passing between the horns of Taurus the Bull and setting before midnight.
The Saint John Astronomy Club meets in the Rockwood Park Interpretation Centre at 7 pm on Saturday, May 4. All are welcome. And, of course, that is Star Wars Day: May the Fourth be with you.
Questions? Contact Curt Nason.