Charles Messier's first catalog entry.
The Crab Nebula is a supernova remnant about 6,500 light years from Earth in the Milky Way. It was first identified in 1731 by John Bevis. The nebula was independently rediscovered in 1758 by Charles Messier as he was observing a bright comet. Messier cataloged it as the first entry in his catalog of comet-like objects. The Crab Nebula is approximately 13 light years long by 9 light years wide and is expanding at a rate of 930 miles per second (over 3 million mph, or 4.8 million kph!).
The stellar explosion that started the expansion of this amazing nebula occurred 962 years ago in 1054 A.D. It was reported by Chinese and Japanese astronomers (it was not recorded by the Europeans of the time). They described sighting an extremely bright new star in the heavens. The star was so brilliant that it was visible even during the day for nearly three weeks, and only faded from view nearly two years later.
The remnant of the original star is an extremely dense, rapidly spinning pulsar (short for pulsating radio star). It is only 20 km in diameter and spins 30 times per second; it has the same mass as our sun. A pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The Crab Pulsar is one of very few pulsars to be identified optically. An amazing Hubble/Chandra composite image of the pulsar can be seen at
Crab PulsarThis is the first narrowband color image I've felt good enough about to post. After a disastrous attempt at the Pelican Nebula I decided to choose a target a little more compact. It's just another M1, but to me it's a small success a long time coming.
Version A HOO
Version B SHO
Version C HOS
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