M1, THE CRAB NEBULA on 2024-10-04+05+07

This photo was taken in Kyle, Texas, under Bortle 5.9 skies, through a 6-inch f/4 Telescope, on a EQ6-R mount, with a ZWO ASI533MC PRO color camera. Plus a dual-band H-Alpha & O-III Filter. The processing was done in PixInsight. The total image acquisition time is: 6 hrs 47 min 30 sec. [Full Size View] Full size files are very large and can take a minute to download. To zoom in or out on a computer, hold down the Ctrl key and use the scroll mouse button, or you can press the + or - key. 

The Crab Nebula is a beautiful supernova remnant. The supernova was noted on July 4, 1054 A.D. by Chinese astronomers, and was about as bright as the Full Moon, and visible in daylight for 23 days. It was probably also recorded by Anasazi Indian artists (in present-day Arizona and New Mexico), as findings in Navaho Canyon and White Mesa (both AZ) as well as in the Chaco Canyon National Park (NM) indicate. Known as Supernova 1054, it was also assigned the variable star designation CM Tauri. The nebulous remnant was discovered by John Bevis in 1731, according to Messier, who independently found it again on August 28, 1758. Messier first thought it was a comet. Of course, he soon recognized that it had no apparent proper motion and cataloged it on September 12, 1758. It was christened the "Crab" due to a drawing made by Lord Rosse about 1844. 

The nebula consists of stellar material ejected in the supernova explosion, which has spread over a volume in space of about 10 light years. It is still expanding at a very high velocity of about 1,800 km/sec. It emits light which consists of two major contributions: A reddish component which forms a chaotic web of bright filaments, which has an emission line spectrum like that of diffuse gaseous (or planetary) nebulae, and a blueish diffuse background of highly polarized "synchrotron radiation", which is emitted by high-energy (fast moving) electrons in a strong magnetic field. Synchrotron radiation is also apparent in other explosive processes in the cosmos, e.g. in the active core of the irregular galaxy M82 and the peculiar jet of giant elliptical galaxy M87.

In 1948, the Crab nebula was identified as a strong source of radio radiation. X-rays from this object were first detected in 1964 with a high-altitude rocket; the energy emitted in X-rays by the Crab nebula is about 100 times more than that emitted in the visual light. Nevertheless, even the luminosity of the nebula in the visible light is enormous: At its distance of 6,300 light years, its apparent brightness corresponds to an absolute magnitude of about -3.2, or more than 1000 times the suns brightness. 

In 1968, a pulsating radio source, named the Crab Pulsar (cataloged as NP0532), was discovered in M1. It has now been established that this pulsar is a rapidly rotating neutron star. It rotates about 30 times per second. The neutron star emits pulses in virtually every part of the electromagnetic spectrum from a "hot spot" on its surface. A neutron star is an extremely dense star, denser than an atomic nucleus. The neutron star that is the engine to the Crab Pulsar contains more mass than our sun in a volume only 30 kilometers across. It's rotation is slowly decelerating by magnetic interaction with the nebula. The magnetic interaction is a major energy source which makes the nebula shine. In visible light, the pulsar is 16th apparent magnitude. This means that this very small star has an absolute magnitude of +4.5, or about the same luminosity as our sun in the visible part of the spectrum! 

Previous, Older Photo

M1, THE CRAB NEBULA on 2007-12-17

Done with my 17.5 inch ALT-AZ Scope and SBIG ST-9E CCD camera

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