NGC 1291 — Galaxy in Eridanus

NGC 1291 is a peculiar early-type barred galaxy on the Eridanus-Hydrus border, about 33 million light-years away. It is the prototype of a class of galaxies that combine the smooth, red, old population of an S0 lenticular with a striking pair of inner and outer rings, the inner ring tightly enclosing a small bar, the outer ring a delicate, almost circular feature surrounding the disk. The contrast between the smooth outer halo and the sharply defined ring structures gives it one of the most distinctive morphologies of any nearby galaxy. At magnitude 8.5 it is one of the brightest non-Messier galaxies in the sky.

Despite its catalog brightness, NGC 1291 has very low surface brightness — its glow is spread over more than 10 arcminutes. From a dark site, a 4-inch telescope at low power shows a soft, large round glow with a noticeable central brightening. An 8-inch reveals the small bright core embedded in the broad halo, but the outer ring is essentially photographic only. At declination -41 degrees it is a southern object, best from latitudes south of about +30. Best observed October through February.

Discovered by James Dunlop on 2 December 1826 from Parramatta. NGC 1291 was historically classified as an S0 lenticular, but Allan Sandage's 1961 Hubble Atlas reclassified it as a peculiar barred galaxy — one of the early objects to challenge the simple split between spirals and lenticulars. Its inner-bar/outer-ring structure became a textbook example in de Vaucouleurs' extended classification scheme.