Tuesday, November 27, 2007

Constellations

Since ancient times, people have tried to find patterns in the stars. Some groups are so distinctive that they have been recognized for as long as 20,000 years!Today 88 constellations are recognized by the western world. Here are three which are currently visible in the northern hemisphere. If you can get away from bright city lights and find a clear night, see if you can spot these four. We'll start with an easy one...


Orion:
Probably the easiest winter constellation to spot, because of the three bright stars in a straight line that make up his belt, Orion is my favorite constellation. It features two of the brightest (first magnitude, star brightness is measured by magnitude) stars in the heavens, Rigel and Betelgeuse. If you follow the line of Orion's belt past Alnitak, you can find Sirius, the Dog Star, the brightest star in the sky. In fact, November's sky is filled with very bright stars.
Just below the center star in Orion's belt is the Orion nebula, one of only two nebulas bright enough to be seen without a telescope. Orion first appears in September, but is now visible well above the horizon by midnight.

Taurus:
An easy way to find this one is to remember that Orion chases Taurus the bull. In fact, people have thought this group of stars looked like a bull since earliest recorded history. Many scientists believe that Stone Age cave paintings in Lascaux, France depict this constellation. It's currently visible just above the horizon, but will rise high in the sky throughout  the winter. Look for Taurus' glowing red eye, the star Aldebaran, in the middle of his face.

Pegasus:
Now almost directly overhead, the great square that makes up the center of Pegasus surrounds a large portion of the midnight sky. This patch of sky is also important because it contains the Andromeda Galaxy, our closest galactic neighbor, only 2.5 million light years away from our own.
The constellation only represents the front half of the legendary winged horse for which it's named. Pegasus in myth was the son of Medusa, the hideously ugly gorgon, whose look could turn men to stone.

Ursa Major:
Probably the most recognized constellation, the Big Dipper is now visible just above the Northern horizon. Originally called "the Great Bear", because the bowl of the dipper resembles a saddle on a bear's back. Above Ursa Major is Ursa Minor, the Little Dipper which contains Polaris, the North Star. 
If you have good vision on a clear night, the middle star in the handle of the Big Dipper appears to flicker. This is because it's actually a binary star, a group of two stars: Mizar and Alcor. 

If you'd like to see my previous posts on astronomy click here.

There's an outstanding book with lots of beautiful, glossy pictures called Astronomy: A Visual Guide, by Mark A. Garlick. Consider it as a holiday gift for a loved one. Buying this or other fine products by traveling through this site to Amazon.com helps support Hansisgreat.

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