Canis Major

March 2014 Constellation of the Month: Canis Major

 

In early March 2014, an hour after sunset, you can see 4 very bright points of light in the southern half of the sky.  Jupiter, currently in the constellation Gemini, is the brightest of these.  South and somewhat west of Jupiter is the last month's Constellation of the Month, Orion.  It has two very bright stars, Betelgeuse and Rigel. 

The southernmost bright object is Sirius, the Dog Star, in the constellation of Canis Major (Big Dog).  Sirius is the brightest star in the sky -- at any time of year, northern or southern hemisphere. It is almost as bright as Jupiter right now.   Although Sirius appears noticeably brighter than Betelgeuse in Orion, it is only 23 times as bright as the Sun.   Betelgeuse is 40,000 times brighter. So Sirius is much closer -- only 8.6 light years (about 50 trillion miles) away.

M41 is an open cluster of 8,000 stars in Canis Major, south of Sirius. It is easily visible with binoculars.

The band of the Milky Way passes through Canis Major, although it is less prominent there than in the "W" Cassiopeia in the North and the summer constellations. This is because when we look at Canis Major, we are looking away from the center of the Milky Way galaxy, and there are fewer stars along the plane of the galaxy in that direction.