Messier 64 — Galaxy in Coma Berenices

M64 (NGC 4826), the Black Eye Galaxy or Evil Eye Galaxy, is a spiral galaxy in the constellation Coma Berenices, located approximately 17 million light-years from Earth. At magnitude 8.5, it is one of the brighter galaxies in Messier's catalog, spanning about 10.7 by 5.1 arcminutes, which corresponds to a true diameter of roughly 54,000 light-years. The galaxy is classified as type (R)SA(rs)ab. Its most famous feature is a prominent dark band of absorbing dust in front of the galaxy's bright nucleus, giving it its distinctive 'black eye' appearance. This dust lane is visible even in modest telescopes. M64 harbors a remarkable secret: its outer gas disk rotates in the opposite direction to its inner disk and stars. This counter-rotation extends from about 3,000 light-years out to at least 40,000 light-years and is believed to be the result of a merger with a smaller satellite galaxy more than a billion years ago. At the boundary where the two counter-rotating regions meet, gas collides and compresses, triggering active star formation visible as a ring of hot blue stars and HII regions.

Located in Coma Berenices, about 1 degree east-northeast of 35 Comae Berenices and about 4.5 degrees northeast of Diadem (Alpha Comae Berenices). M64 is relatively easy to find and observe. In binoculars, it appears as a bright, compact fuzzy spot. A 4-inch telescope at 100x shows an oval glow with a conspicuously bright core. The famous dark dust band, the 'black eye,' becomes visible in 6-inch telescopes at moderate to high magnification (150x or more) as a dark patch on the north side of the nucleus. With 8 inches and above, the dust lane is prominent and unmistakable. Best observed from March through July.

Discovered by Edward Pigott on March 23, 1779, making it one of the few Messier objects discovered by Pigott. Johann Elert Bode independently found it on April 4, 1779, and Charles Messier cataloged it on March 1, 1780. The counter-rotating disk was discovered in 1992 through detailed spectroscopic observations, revealing the merger history hidden within this seemingly normal-looking galaxy.