The Whirlpool Galaxy, also known as M51, is very popular among stargazers as well as professional astronomers. It's one of the larger galaxies in our sky, about half the size of our moon. It's face-on to us which means we get an excellent view of its spiral structure.
More unusually, M51 has a fairly large companion, named NGC 5195, that is so close that they appear to be touching. One theory explains that the Whirlpool Galaxy gave birth to NGC 5195 because of the interaction of different sets of black holes within and these two galaxies now orbit each other.
At a distance of about 25 million light years, binoculars or a telescope and a dark site are needed to watch the action.
Viewing Whirlpool Galaxy
Early April to early June
A dark site is essential. Although the Whirlpool Galaxy is in Canes Venatici, we use the Big Dipper in Ursa Major to find it. Find the end star of the Dipper's handle, Alkaid. Find a star about 3° (2 finger-widths) below Alkaid. Use these two stars to form an isosceles triangle with the Whirlpool Galaxy as the third point. See the map above.
Look for a small smudge of light.
Look for the glow of two galaxy cores that appear like twin headlights of a vehicle in the fog. With a large enough telescope, view the spiral structures. Challenge: see if you can spot the bridge of nebulosity that appears to connect the galaxies. Try drawing what you see; this can help you see more detail.