Saturday, September 15, 2012

Sept. 2012 Constellation of the Month - Sagittarius

We can use our either our July constellation of the month -- the Summer Triangle --  or our August constellation -- Scorpius --  to find our September constellation of the month – Sagittarius.  The Summer Triangle points south to a spot just east of the teapot-shaped Sagittarius, which, in turn, is just east of Scorpius.  Sagittarius is easy to recognize, being compact in shape and comprised of moderately bright stars.

Sagittarius is unique in at least one respect: when you look in the direction of Sagittarius, you are looking toward the center of our Milky Way Galaxy.  Not surprisingly, the band of the Milky Way appears brightest in that direction.  

The center of our galaxy is about 27,000 light years from the Earth – or 27,000 times 6 trillion miles.  At the center is a super-huge black hole with a mass of about 4 million of our Suns.  It is constantly adding to its mass by sucking in everything which is "nearby" by astronomical standards, including stars, nebulae and other black holes.

Sagittarius has several nebulae and star clusters which can be seen in small telescopes, such as those we use in Discovery Center astronomy events.  The most famous of these are the spectacular Lagoon Nebula, Omega Nebula and Trifid Nebula.

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