Universe Today - 2010 March 07
Way out yonder some 40 to 50 million light years away in the constellation of Canes Venetici is a pair of interacting galaxies sometimes referred to as "The Cocoon". These two mis-shaped blobs of star stuff have already made their closest approach to each other and are now parting ways. Between them stretches a trail of stars that spans some 24,000 light years as they face each other showing off their numerous star-forming regions. But where there is life… There is death. Let's put our finger right on the pulse of a supernova.
...
Supernova 2008ax in NGC 4490 was quite an event. The neophyte supernova was discovered independently by both the Lick Observatory Supernova Search and by astronomer Koichi Itagaki of Japan. At its beginning pulse it was believed to have been a blue variable – but the spectrum doesn't lie. Soon enough the phenomena went to a young type II supernova and escalated into a type Ib. Although the pulse might have been faint – dangling between magnitude 13 and 16 – it was there and undeniable.
NGC 4490/4485 – SN 2008ax - T. Grossman, D. Hager and R. Johnson