Helix galaxy — Galaxy in Ursa Major

NGC 2685 is a rare polar-ring galaxy in the constellation Ursa Major, about 42 million light-years away. Popularly called the 'Helix Galaxy' or the 'Pancake Galaxy,' it features a central lenticular stellar disk encircled by a roughly perpendicular ring of gas, dust, and young stars — an arrangement thought to form when a small gas-rich galaxy is consumed in a retrograde orbit around a larger one. Only a few dozen galaxies showing this clean polar-ring geometry are known, and NGC 2685 is the prototype of the class and one of the brightest examples visible from Earth.

A challenging target that rewards aperture. At magnitude 11.1 it is within reach of 6-inch telescopes, but the polar ring is too faint for visual observation at modest apertures — in a 6-inch scope only the cigar-shaped central disk is clearly visible. A 12-inch telescope under dark skies begins to reveal the perpendicular ring as a faint brightening crossing the main body. Photographically the structure is obvious even in short DSLR exposures. The galaxy lies about 2 degrees north of the brighter M81/M82 pair, making it an easy star-hop extension of that famous session. Best observed January through June.

Discovered by William Herschel on August 18, 1789. Its unusual 'spindle-with-halo' appearance was noted throughout the 19th century but not understood. In 1959 Fritz Zwicky pointed out the strange edge-on ring; in the 1970s, observations by Vera Rubin and others confirmed the ring rotates in a plane nearly perpendicular to the main disk. The polar-ring interpretation — a merger remnant — became the standard model in the 1980s after detailed kinematic studies.