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What’s Up for November?
What’s up for November: the Crab Nebula.
Hello and welcome. I’m Jane Houston Jones at NASA’s Jet Propulsion Laboratory in Pasadena, California.
2009 is the International Year of Astronomy.
And this month’s special viewing target is the Crab Nebula, the only supernova remnant that’s easy to see from a modest telescope.
In 1758 Charles Messier was scanning the skies for Comet Halley.
He noticed a whitish light shaped like the flame of a candle in the constellation Taurus.
He soon noticed it wasn’t moving against the background stars. So it couldn’t be the comet.
M1 became the first entry in his catalog of 110 comet-like objects.
This object was discovered in 1731 by English amateur astronomer John Bevis...
and sketched by Irish astronomer William Parsons, the Third Earl of Rosse, in 1844 through his big 36-inch reflector telescope.
His sketch resembled a crab, and the name Crab Nebula stuck.
The history of this object goes back even further.
A “guest” star was visible in the summer sky of 1054.
Ancient astronomers in both the old and new worlds documented a bright new star in the daytime sky.
It was a supernova in the constellation Taurus and was visible with the unaided eye for nearly two years.
In the 1940’s the 100-inch Hooker Telescope at Mt. Wilson was used to compute back to when the Crab Nebula first began to expand.
It began near the time of the supernova of 1054.
At the center of the nebula is a rapidly-spinning neutron star or pulsar, which emits pulses of radiation 30 times a second.
In 1967 British astronomy graduate student Jocelyn Bell discovered this first pulsar.
Three of NASA’s great observatories show that the super-dense neutron star is energizing the expanding nebula.
The Chandra X-ray image traces the most energetic particles. The white dot in the center is the pulsar.
Spitzer’s infrared image traces the cloud of electrons trapped within the star’s magnetic field.
And the Hubble Telescope’s image in visible light is one of the largest images taken by Hubble’s Wide Field and Planetary Camera 2.
The Crab Nebula is faint, but it can be seen with binoculars if your sky conditions are really good.
Aim your binoculars at the red giant star Aldebaran in Taurus.
Draw a straight line out to the southernmost of the bull’s horns.
And the Crab Nebula is right next to that star.
You’ll see a fuzzy patch shaped like the flame of a candle.
It’s difficult, but not impossible, to see the faint neutron star within the Crab Nebula.
If you can see two stars, the fainter of the two is the Crab pulsar.
It’s one of the few historically-observed supernovae in our Milky Way Galaxy. So go out and try to see it!
On November 17, if you can get away from city lights, you’ll have a great view of the annual Leonid Meteor shower.
After midnight local time you should see lots of shooting stars.
You can learn all about NASA's missions at www.nasa.gov
That’s all for this month, I’m Jane Houston Jones.
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