M64: The “Black-Eyed” Galaxy

One of the finer sights in the spring sky, the spiral galaxy M64 in Coma Berenices reveals to a keen observer a striking dust lane that gives the appearance of a “black eye” in intergalactic space.

The Basics

• M64 is a spiral galaxy of type Sb, located 19 million light years from Earth, with an outer radius of 40,000 light years.

• At magnitude 8.5, M64 is visible with binoculars in dark skies. You’ll need at least a 6” scope to see the “eye” of the outer dust lanes. Make sure to keep your eyes “dark adapted”. And use higher magnification… it works best, especially in light-polluted skies

• M64 is located at RA +12h 36m 20.6s, Dec +25d 59m 20s. You’ll find it two-thirds of the way between 35 Coma and 40 Comae, closer to the former.

Hubble Telescope Image of Messier 64

A Deeper Look

• In the 1990′s, astronomers discovered the dark gas in the outer region of M64 rotates opposite to the gas and stars in the inner region.

• Why this strange counter-rotation? M64 likely absorbed a small nearby galaxy about a billion years ago. In Hubble photos, you can see the shear region between the two oppositely rotating streams has become a remarkably productive star-forming region.

A Bit of History

The name “black eye” comes from William Herschel’s description of M64 upon seeing it with his immense reflector in the late 18th century: “A very remarkable object, much elongated… and contains one lucid spot like a star with a small black arch under it, so that it gives one the idea of what is called a black eye, arising from fighting.”

Personal View

From my light-polluted location, I need patience, clear sky, and high magnification to see this gem. But the thrill I get upon glimpsing the “black eye” is always worth the effort. If you have a 6” or larger scope, give it a try. With a small telescope, M64 is a great test of your observing skill.