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Wildrik Botjes Planetarium
Physics & Astronomy Department

Astr110 Photography Projects, Spring 2006

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Crab Nebula, Diane Bunque

Crab Nebula

The Crab Nebula (also known as Messier Object 1, M1 or NGC 1952) is a gaseous diffuse nebula in the constellation Taurus. It is the remnant of a supernova that was recorded by Chinese and Arab astronomers in 1054 as being visible during daylight for 23 days. Located at a distance of about 6500 ly from Earth, it's linear size is approximately 8 ly by 11 ly. A neutron star in the centre of the nebula rotates 30 times per second.

The Crab Nebula is often used as a calibration source in X-ray astronomy. It is very bright in X-rays and the flux density and spectrum are known to be constant, with the exception of the pulsar. The pulsar provides a strong periodic signal that is used to check the timing of the X-ray detectors. In X-ray astronomy, 'Crab' and 'milliCrab' are sometimes used as units of flux density. Very few X-ray sources ever exceed one Crab in brightness.

References:
http://en.wikipedia.org/wiki/Crab_nebula

Right Ascension (J2000) 05:34:30
Declination (J2000) +22:01:00
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 5x60 seconds in C, 600 seconds in BVR
Date observed March 13, 2006 (C)
March 13, 2006 (B)
March 20, 2006 (VR)