Jimmy Westlake: The teapot at the end of the Milky Way
July 21, 2014
Steamboat Springs — Legend has it that a pot of gold awaits you at the end of the rainbow, if you are lucky enough to find it.
No luck at all is required, though, to find the pot of tea at the end of the Milky Way. All you need is a clear, dark night and an unobstructed view of the southern sky.
When the last rays of the summer sun fade from the evening sky, the misty star clouds of the Milky Way come into view, arching high overhead like a colorless rainbow. Follow this milky river down toward the south, and there you will find the zodiacal constellation of Sagittarius, the Archer.
Our ancient ancestors imagined a wise centaur in these stars — half man, half horse — holding a bow and arrow aimed directly at the heart of the nearby Scorpion. I challenge anyone to look at those stars and find a centaur holding a bow and arrow.
Instead, most modern sky watchers find it much easier to imagine the outline of a teapot, formed from eight prominent stars. The steamy star clouds of the Milky Way seem to be boiling right out of the teapot's spout, as it tips over to pour its scalding-hot contents onto the tail of the Scorpion to the west.
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The five stars that make up the teapot's handle and lid form another delightful little asterism called the Milk Dipper, which bears a striking resemblance to its bigger cousin to the north.
About a hand-span to the left, or east, of the teapot is a quartet of stars that looks like a tiny crucifix, so small that you can hide it behind your thumb. Its nickname is the Terebellum because of its resemblance to the tiny mollusk of the same name.
Check this one out with your binoculars. It's one of my favorite asterisms in the whole sky.
Sweep your binoculars around the stars of the teapot, and you'll discover a swarm of colorful nebulae and star clusters. The Great Sagittarius Star Cluster, M22, is one of the finest globular star clusters in the sky, just east of the teapot's top star.
M22 looks like the fuzzy head of a dandelion through binoculars and contains more than half a million stars, about 10,000 light-years away.
Just above the spout of the teapot is M8, a magnificent glowing cloud of pink hydrogen gas called the Lagoon Nebula. Many other beautiful star clusters, like M6, M7, M23 and M25, adorn the area around Sagittarius, as well.
With all of the celestial treasures that Sagittarius and its teapot asterism have to offer, maybe there is a pot of gold at the end of the Milky Way after all.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out Westlake’s astrophotography website at http://www.jwestlake.com.