M1-1

About this image 

This image of the well-known Crab Nebula was taken using Ektachrome
film at the prime focus of the Kitt Peak 4-meter telescope on October
1st 1973. This is unusual because most astronomical pictures are
coloured by combining three different exposures taken through red,
green and blue filters. In this relatively short exposure, the pulsar
is clearly visible (slightly below and to the right of the central
star, which is actually a projected foreground object). North is up
with east to the left.

About this object

The Crab Nebula was originally given this name due to its resemblance
to a crab's claw (not the full-body image of a crab), in an early
sketch made in 1855 by Lord Rosse's staff astronomer
R.J. Mitchell. With higher resolution pictures, this appearance became
far less compelling, but the name has stuck.  It is the remnant of a
supernova explosion in the year 1054 A.D., which was recorded in five
separate accounts from Chinese astronomers in the Far East. It is
perhaps odd that no western observation has survived, since it was
certainly one of the most spectacular historical supernovae. The red
tendrils are excited gas, emitting strong H-alpha radiation. The
nebula was probably first noticed in 1731 by John Bevis, and it was
significant enough to be the first entry in Charles Messier's list of
nebulae (compiled to avoid mistaking them for comets). The nebula
continues to expand and change the details of its appearance, and this
is partly due to the violence of the original explosion. However, the
star which exploded left behind a rotating neutron star, which
continues to beam energy out into the nebula, as well as flashing with
a period of only 33 milliseconds. The details of this energy input are
important for our understanding both of neutron stars and of the
physical conditions in the nebula, and are revealed in the patterns of
filaments, their brightness and colors, and the way they change with
time.  Despite the name, it is actually in the constellation Taurus.

Photograph by Bill Schoening.

Minimum credit line: Bill Schoening/AURA/NOAO/NSF (for details see
Copyright Statement)