The M1 Crab Nebula was the first object to be catalogued by Charles Messier in 1758. However, historical records suggest that Asian astronomers observed it first in 1054 when it became visible as a new star, bright enough to be seen in the daytime. A remnant of a supernova, its name is taken simply because Irish astronomer William Parsons’ initial sketch taken in 1848 resembled a crab, and the name has stuck ever since. The Crab Nebula lies in the constellation of Taurus, but its distance is difficult to gauge. The best guess is that it is between 6000 and 7000 light years away. It is roughly 13 light years across, and is seen as an expanding shell of glowing filaments made up of ionised helium, hydrogen, carbon, oxygen and other assorted elements. At its centre sits what remains of the progenitor star. Now a pulsar measuring 30km across, it spins once every 33 milliseconds. It fires bursts of electromagnetic radiation from its poles which help illuminate the Crab Nebula to 75,000 times the luminosity of our sun, and cause a shock front that changes the appearance of the nebula almost daily. An intriguing mystery suggests that the combined mass of the nebula and the pulsar do not actually add up to the predicted mass of the progenitor star, with estimations suggesting that the progenitor star could have lost up to 5 times the mass of our own sun before it went supernova. To date nobody knows how or why, nor do they know where this large amount of material went.

Article researched by Craig Grice.

This image was taken over 5 evenings in late December 2011 comprising 24 x 7 minute images @ ISO 1600 with a Canon 40D DSLR and an 8" Ritchey Chrietien Astrograph and 0.8 focal reducer / flatner making an F/6.4 instrument. Star defraction spikes are software created.