Early in June, 2011, a supernova appeared in Messier 51, the Whirlpool Galaxy in Canes Venatici. When large stars reach the end of their lives, they can explode in a tremendous burst of energy. For a while, a single supernova can appear as bright as the entire galaxy of which it is a part. This supernova is expected to stay bright for a few weeks before slowly dimming and disappearing from our sight.
This supernova is about magnitude 14, which is bright enough to be seen with medium-sized amateur telescopes. To understand how very bright this star is, you need to realize that all the other stars in this image are part of our own Milky Way galaxy, and they are probably at most a few thousand light years away. We can estimate that the Whirlpool Galaxy and its supernova are least 60,000 times farther away than the foreground stars.
| Magnitude | 8.1 |
| Apparent Size | 11' x 8' |
| Distance (light yrs) | 23 million |
| Right Ascension | 13:29.9 |
| Declination | +47 12 |
Image details: 12 images, each 300 seconds at ISO 1600, taken with a Canon 400D camera through a Meade 12” telescope at f/6.7.
June 6, 2011