NGC 4631 is an edge-on barred spiral galaxy in the constellation Canes Ventatici. It has the uncanny appearance of a large baleen whale seen in profile, complete with nebula comprising its eye, a cluster of blue stars for a pectoral fin, and even a haze above the blow hole that could represent a spout. It has a companion dwarf galaxy NGC 4627, which is often called the pup, even though a baby whale is supposed to be a calf. The center of the galaxy is a region of intense star formation, probably as a result of gravitational interaction between the them. The distance to the galaxies is about 30 million light-years.

Exposures: L:R:G:B =350:120:120:110 =11 hours 40 minutes total exposure at f/8.3

This image was published as a Picture of the Day on Astronomy.com