M27
The Dumbbell Nebula

Discovered by Charles Messier in 1764.

The Dumbbell Nebula M27 was the first planetary nebula ever discovered. This planetary nebula is certainly the most impressive object of its kind in the sky, as the angular diameter of the luminous body is nearly 6 arc minutes, with a faint halo extensing out to over 15', half the apparent diameter of the Moon.

The bright portion of the nebula is apparently expanding at a rate of 6.8 arc seconds per year, leading to an estimated age of 3000 to 4000 years, i.e. the shell ejection probably would have been observable. As for most planetary nebulae, the distance of M27 (and thus true dimension and intrinsic luminosity) is not very well known. Currently, investigations with the Hubble Space Telescope are under work to determine a more reliable and acurate value for the distance of the Dumbbell Nebula.

Source: seds.org