Messier 64: The Black Eye Galaxy

The Black Eye Galaxy is a bright spiral in Coma Berenices with a dark band of dust next to its core, like a bruise under an eye. It is one of the few galaxies where a modest telescope shows a distinct feature, which makes it a favorite spring target.

What it is

M64 is a spiral galaxy about 17 million light-years away. Its 9.3-arcminute length works out to roughly 46,000 light-years. The "black eye" is a thick lane of dust lying in front of the bright central region and blocking its light. M64 is also unusual in how it moves: the gas in its inner disk turns in one direction, while the gas in the outer disk turns the opposite way. Where the two meet, the gas is compressed and new stars are forming. A likely explanation is that M64 absorbed a smaller galaxy long ago whose material has not yet settled into the main disk. It is also nicknamed the Sleeping Beauty Galaxy.

When to see it

M64 is a spring object. It is highest around midnight in early April and well placed in the evening from April through June. From about 40°N it climbs to about 72° in the south. From the Southern Hemisphere it is visible low in the northern sky during their autumn.

How to find it

The key star is 35 Comae Berenices, a 5th-magnitude star. To reach it, start at Alpha Comae Berenices (Diadem) and move about 5° to the northwest. M64 is just under 1° east-northeast of 35 Comae, so both fit in a low-power finder field. M53, a globular cluster, lies about 1° northeast of Alpha Comae if you want to add a second target.

What you will see

Good binoculars under dark skies show M64 as a small oval glow. A small telescope shows a bright, elongated oval with a bright core. On a dark, steady night a 100 mm telescope at medium power can show the dark lane as a slight dimming on one side of the core. A 200 mm telescope shows the black eye clearly as a dark curved patch just off the bright center. The galaxy itself is easy from the suburbs, but the dust lane is much easier from a dark site.

History

Edward Pigott discovered M64 on March 23, 1779. Johann Elert Bode found it on his own 12 days later, on April 4, and Charles Messier found it again on March 1, 1780. Pigott's discovery went largely unnoticed until historians rediscovered it in 2002. William Herschel, observing it in the 1780s, noticed the dark feature and compared it to a black eye.