October 2012 Constellation of the Month - Cygnus

Our July 2012 "constellation" of the month, the Summer Triangle, is still high in the sky in October.  Three months later, one would have expected the earth's rotation around the sun to make it appear more to the West.  But, if we're looking at the sky soon after it gets fully dark, we're now looking upwards at about 7:30 PM instead of about 9:30.  So the earth's daily rotation has had 2 fewer hours to move it toward setting in the West.  

The westernmost star in the Triangle is Deneb, in the constellation of Cygnus, the swan.  Cygnus has the shape of a cross and is sometimes called the "Northern Cross".  (There is also a constellation, Crux, popularly known as the "Southern Cross", which is visible to those living in the southern hemisphere of the earth.)  Deneb is at the top of the cross. It is a blue giant star, and it is about 100,000 times brighter than our sun.  

The hazy band of the Milky Way is prominent in Cygnus.  It appears to split in two there, because of the presence of a dark cloud of dust known as the Cygnus Rift, or the Northern Coalsack.  (You guessed it: there is also a Coalsack in the southern sky).   If you follow the Milky Way band to the North and East, you'll see the W-shaped constellation Cassiopeia, which was our constellation of the month for December 2011.  

The foot of the cross is Albireo, which can be seen as a beautiful orange and blue double star in a small telescope, such as those you can look through at a Discovery Center event.  Omicron Cygnii is an orange, blue, and blue triple star. The North American Nebula (shaped like you-know what) and the Veiled Nebular are also in Cygnus.  A powerful source of radio waves (but not seen in visible light), A Cygnii, is a collision of two galaxies, millions of light years away.  Eta Cygnii is an intense X-ray source thought to be caused by a black hole orbiting a blue supergiant star.