The supernova was noted on July 4, 1054 A.D. by Chinese astronomers as a new or "guest star," and was about four times brighter than Venus, or about mag -6. According to the records, it was visible in daylight for 23 days, and 653 days to the naked eye in the night sky.
At X-ray and gamma-ray energies above 30 KeV, the Crab is generally the strongest persistent source in the sky, with measured flux extending to above 1012 eV. Located at a distance of about 6,500 light-years (2 kpc) from Earth, the nebula has a diameter of 11 ly (3.4 pc) and expands at a rate of about 1,500 kilometers per second.
At the center of the nebula lies the Crab Pulsar, a neutron star (or spinning ball of neutrons), 28-30km across,[5] which emits pulses of radiation from gamma rays to radio waves with a spin rate of 30.2 times per second. The nebula was the first astronomical object identified with a historical supernova explosion.
The cloudy remnants of SN 1054 are now known as the Crab Nebula. The nebula is also referred to as Messier 1 or M1, being the first Messier Object catalogued in 1758.
Instruments and exposure data
W.O FLT110 with dedicated TMB field flattener and FeatherTouch 3'' focuser
Filter Astrodon Hα 5nm
SBIG ST10XME CFW9
Starizona MicroTouch autofocuser
EQ6
Hα:10*15min(bin1x1) total 2h30min
Kallithea Athens Hellas
Astrobin Image of the Day 22 May 2014
