NGC 651 (also known as Messier 76, Barbell Nebula, Little Dumbbell Nebula, NGC 650 and Barbell Nebula) is a magnitude +10.1 planetary nebula located 2500 light-years away in the constellation Perseus.
The galaxy was discovered by French astronomer Pierre Méchain using a 15.24 cm (6 inch) speculum newtonian reflector on the 5th September 1780. Charles Messier also observed the planetary nebula in 1780. The planetary nebula was rediscovered by William Herschel in November 1787.
Right Ascension 01h 42m 18.1s, Declination +51° 34' 31"
It was first recognised as a planetary nebula in 1918 by the astronomer Heber Doust Curtis. However, there is some contention to this claim, as William Huggins, through spectroscopy, realised that the object was gassy; and Isaac Roberts, a pioneer of astrophotography, in 1891 concluded that the object was not double and suggested that M76 might be similar to the Ring Nebula (M57), being instead seen from a side view. The structure is now classed as a bipolar planetary nebula (BPNe). It was originally thought to consist of two separate emission nebulae and was thus given two catalogue numbers; NGC 650 and NGC 651. Some consider this object to be one of the faintest and hardest objects to see in Messier's list. Read more
Position(2000): RA = 1°41′ 58.8" Dec = 51°34′ 32.94"
M76 is recognised as a planetary nebula - a gaseous shroud cast off by a dying sunlike star. The nebula itself is thought to be shaped more like a donut, while its box-like appearance is due to our nearly edge-on view. Distance estimates place M76 about 3 to 5 thousand light-years away, making the nebula over a light-year in diameter.