Changes

  | dec = {{DEC|+22|00|52.2}}<ref name="simbad" />

  | dec = {{DEC|+22|00|52.2}}<ref name="simbad" />

  | dist_ly = {{val|6500|1600}}

  | dist_ly = {{val|6500|1600}}

  | dist_pc = {{val|2000|500}}<ref name="Kaplanetal2008">{{cite journal |last1=Kaplan |first1=David L. |last2=Chatterjee |first2=S. |last3=Gaensler |first3=B. M. |last4=Anderson |first4=J. |title=A Precise Proper Motion for the Crab Pulsar, and the Difficulty of Testing Spin-Kick Alignment for Young Neutron Stars |journal=[[The Astrophysical Journal]] |volume=677 |issue=2 |pages=1201–1215 |date=2008 |arxiv=0801.1142 |doi=10.1086/529026 |bibcode=2008ApJ...677.1201K|s2cid=17840947 }}</ref>

  | dist_pc = {{val|2000|500}}<ref name="Kaplanetal2008">{{cite journal |last1=Kaplan |first1=David L. |last2=Chatterjee |first2=S. |last3=Gaensler |first3=B. M. |last4=Anderson |first4=J. |title=A Precise Proper Motion for the Crab Pulsar, and the Difficulty of Testing Spin-Kick Alignment for Young Neutron Stars |url=https://archive.org/details/sim_astrophysical-journal_2008-04-20_677_2/page/1200 |journal=[[The Astrophysical Journal]] |volume=677 |issue=2 |pages=1201–1215 |date=2008 |arxiv=0801.1142 |doi=10.1086/529026 |bibcode=2008ApJ...677.1201K|s2cid=17840947 }}</ref>

  | appmag_v = +8.4

  | appmag_v = +8.4

  | size_v = 420″ × 290″

  | size_v = 420″ × 290″

The creation of the Crab Nebula corresponds to the bright '''SN 1054''' supernova, which was recorded by Chinese astronomers in 1054 AD. The Crab Nebula itself was first observed in 1731 by John Bevis. The nebula was independently rediscovered in 1758 by [[Charles Messier]] as he was observing a bright [[comet]]. Messier catalogued it as the first entry in his [[Messier Catalogue|catalogue]] of comet-like objects. The [[William Parsons, 3rd Earl of Rosse|Earl of Rosse]] observed the nebula at [[Birr Castle]] in 1848, and referred to the object as the Crab Nebula because a drawing he made of it looked like a crab.<ref>

The creation of the Crab Nebula corresponds to the bright '''SN 1054''' supernova, which was recorded by Chinese astronomers in 1054 AD. The Crab Nebula itself was first observed in 1731 by John Bevis. The nebula was independently rediscovered in 1758 by [[Charles Messier]] as he was observing a bright [[comet]]. Messier catalogued it as the first entry in his [[Messier Catalogue|catalogue]] of comet-like objects. The [[William Parsons, 3rd Earl of Rosse|Earl of Rosse]] observed the nebula at [[Birr Castle]] in 1848, and referred to the object as the Crab Nebula because a drawing he made of it looked like a crab.<ref>

{{cite journal|author=Glyn Jones, K.|year=1976|title=The search for the nebulae|journal=Journal of the History of Astronomy|volume=7 |pages=67|doi=10.1177/002182867600700111|bibcode=1976JHA.....7...67B|s2cid=125142606}}</ref><ref>{{cite web|last=Rossi|first=B.B.|title=The Crab Nebula ancient history and recent discoveries|url=http://ntrs.nasa.gov/search.jsp?R=19700008151|work=NASA|date=October 1969 |publisher=NTRS}}</ref>  

{{cite journal|author=Glyn Jones, K.|year=1976|title=The search for the nebulae|journal=Journal of the History of Astronomy|volume=7 |pages=67|doi=10.1177/002182867600700111|bibcode=1976JHA.....7...67B|s2cid=125142606}}</ref><ref>{{cite web|last=Rossi|first=B.B.|title=The Crab Nebula ancient history and recent discoveries|url=http://ntrs.nasa.gov/search.jsp?R=19700008151|work=NASA|date=October 1969 |publisher=NTRS}}</ref>  

[[File:The Crab Nebula NASA.ogv|thumb|left|thumbtime=6|The Crab Nebula video by [[NASA]]]]

[[File:The Crab Nebula NASA.webm|thumb|left|thumbtime=6|The Crab Nebula video by [[NASA]]]]

In the early 20th century, the analysis of early photographs of the nebula taken several years apart revealed that it was expanding. Tracing the expansion back revealed that the nebula must have become visible on Earth about 900&nbsp;years ago. Historical records revealed that a new star bright enough to be seen in the daytime had been recorded in the same part of the sky by Chinese astronomers in 1054.<ref name="Mayall">

In the early 20th century, the analysis of early photographs of the nebula taken several years apart revealed that it was expanding. Tracing the expansion back revealed that the nebula must have become visible on Earth about 900&nbsp;years ago. Historical records revealed that a new star bright enough to be seen in the daytime had been recorded in the same part of the sky by Chinese astronomers in 1054.<ref name="Mayall">

File:M1.gif|Slow-motion video of the Crab Pulsar, taken with OES Single-Photon-Camera.

File:M1.gif|Slow-motion video of the Crab Pulsar, taken with OES Single-Photon-Camera.

File:The Crab Nebula - A Flickering X-ray Candle.ogv|Data from orbiting observatories show unexpected variations in the Crab Nebula's X-ray output, likely tied to the environment around its central neutron star.

File:The Crab Nebula - A Flickering X-ray Candle.webm|Data from orbiting observatories show unexpected variations in the Crab Nebula's X-ray output, likely tied to the environment around its central neutron star.

File:NASA's Fermi Spots 'Superflares' in the Crab Nebula.ogv|NASA's [[Fermi Gamma-ray Space Telescope]] spots 'superflares' in the Crab Nebula.

File:NASA's Fermi Spots 'Superflares' in the Crab Nebula.webm|NASA's [[Fermi Gamma-ray Space Telescope]] spots 'superflares' in the Crab Nebula.

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== References ==

== References ==