Messier 76 ~ The Little Dumbbell Nebula
Optics:   Ritchey–Chrétien 20" F/8.2 (4166mm FL) Processing:   PixInsight, Photoshop
Camera:   SBIG STXL-11000 with Adaptive Optics Date:   October 2022
11 Megapixel (4008 x 2672 16-bit sensor) Location:   Columbus, Texas
Exposure:   LRGB = 800:130:110:120 minutes Imager:   Kent E. Biggs
M76 (short for Messier 76) is also known as the Little Dumbbell Nebula due to its shape appearing similar to M27, The Dumbbell Nebula, when viewed visually through a telescope. M76 is a Planetary Nebula located in the direction of the constellation Perseus, the mythological Greek hero who slew Medusa the Gorgon. M76 also bears the names of NGC 650 and NGC 651 in the New General Catalog of Nebulae and Clusters of Stars, since it was originally thought to be two objects (one for each loop visible).

While M76 was cataloged as a Messier object by Charles Messier, it was actually discovered by French astronomer Pierre Mechain, who became good friends with Messier and discovered nearly a quarter of the objects in Messier’s catalog of over 100 early deep sky objects. Both astronomers were interested primarily in finding comets, so they cataloged objects such as M76 to avoid being mistaken as a comet.

This image shows material ejected by its central star as it approaches its death. M76 is somewhat unique in that it is a great example of a reasonably bright planetary nebula that is bipolar, meaning it has not just one but two stars which have and continue to eject large amounts of material, leaving neutron or white dwarf stars behind as visible in both the image and the enlarged inset*. The brightest central star visible, HD 10346, is about star magnitude 16 or about 10 thousand times fainter than the faintest star visible with the human eye!

M76 is only about 2500 light years away, thereby it is about 1.25 light years across at its visual widest. Based on my calculation of angle between the two visible central stars of 1.44 arc seconds (or 0.0004 degrees), the distance between the two stars is 100 billion miles or about 6 light days! That is about 30 times the distance to Pluto!  Over the next few thousands of years, the nebula will continue to expand until it dissipates into deep space; its central stars will likewise fade over time.

*Using a mouse, hover over the images above and below for annotations, insets, and enlargements. The image below compares M76 to its namesake big brother, M27, The Dumbbell Nebula!  This hover feature may be unavailable on smart phones.