: Crab Nebula (M1) is in constellation Taurus was a supernova in 1054. Since reminant of this star is neutron star which also called pulsar. Most supernova is comes from red supergiant star before the explosion of the star. Before the explosion in 1054 there must have been a red star shining in the same location in the constellation Taurus. How come nobody ever recorded or reported any red star in the location of Crab Nebula before 1054. Since stars are listed in Greek Alphabet so this star must been listed.

A typical supernovae rises about 19 magnitudes in brightness The supernovae of 1054 reached about -5 magnitude this means that the star in question would have been about 14th magnitude. put another way it was about 1000000 times fainter than a star just visible to the naked eye.