Spiral galaxy in Canes Venatici. The Whirlpool Galaxy is one of the brightest examples of a face-on spiral galaxy visible in our skies. It is estimated to be about 23 million light years away--close enough that its spiral arms can be distinctly seen with a telescope of moderate aperture. The irregular companion galaxy that appears to be connected to one of the spiral arms is NGC 5195. The companion galaxy is actually slightly farther away--notice that the dust lanes in the Whirlpool's arm are seen in silhouette, obscuring some of the light coming from NGC 5195. Some computer simulations suggest that these two galaxies collided many millions of years ago, and that the Whirlpool's spiral structure is a result of that interaction. A few very small and presumably very distant galaxies can also be seen in this image if you look closely.
For comparison, below is an image taken 3 years earier, with a different camera.
