Teapot points way to many celestial targets
Sagittarius is a classic summertime constellation, and this is the best time of year to see what the Greeks portrayed as a centaur aiming an arrow.
It's what I call a "low rider" in our southern Butler sky, rising in the southeast and setting in the southwest and never making it more than 25 to 30 degrees above the southern horizon.
This time of summer, Sagittarius starts out after evening twilight just above the direct southern horizon. You certainly won't crane your neck viewing Sagittarius.
Allegedly, you're supposed to envision a menacing centaur shooting an arrow at its neighboring constellation Scorpius the Scorpion — at least that's how the early Greeks saw it. Now, if you're not quite up to speed on your mythological monsters, a centaur is creature that has the head of a man or woman, and the body of a horse.
But forget about all that! Sagittarius looks just like teapot.
Anybody I've ever shown this constellation says the same thing. It's easy to see because most of the stars are nearly as bright as those in the Big Dipper. There are three stars on the right side that form the spout, four stars on the left side that outline the handle and one star that marks the top of the teapot. It looks as if the teapot is pouring hot celestial tea on the stinger of neighboring Scorpius to the west, causing its tail to curl.
One of the noteworthy stars of Sagittarius is Nunki, positioned on the upper left hand corner of the teapot's handle, It's pronounced "NUN-key" and is one of the cuter star names. Most traditional star names are Arabic, Greek or Latin, but Nunki is a Babylonian name.
Even though it has a cute name, it's one powerful star 230 light-years away. Nunki has a diameter of more than 4 million miles, more than five times that of the sun. It's also more than seven times as massive as our sun, and get this, Nunki kicks out more than 3,000 times the light of our home star.
Sagittarius is not only a fun little constellation, but it also literally points to the downtown neighborhood of our Milky Way galaxy. In fact, the spout of the teapot points right at the central point of our home galaxy. Now, if you're lucky enough to be viewing Sagittarius in the countryside away from incessant light-polluted city skies, you'll clearly see the band of light we call the Milky Way arching from the northeastern horizon to near the overhead and on down to Sagittarius in the south.
Every single star we see in our sky anytime of year is a member of our Milky Way, which is made up of nearly 500 billion stars, but the Milky Way band we see is the combined light of billions of stars that make up the central plane of our galaxy. The region around Sagittarius is in the direction of the hub of our disk-shaped spiral galaxy.
You would think part of the sky around Sagittarius would be really bright, but dark interstellar clouds of gas and dust block our view of the Milky Way's center. It's been said that if we could see the center unobstructed, that part of the sky would be brighter than a full moon!
What astronomers know about the center of our galaxy comes from radio and X-ray astronomy from Earth-based observatories as well as orbital observatories like the Chandra X-Ray telescope.
The nucleus of our home galaxy is a region of chaos that takes a gifted imagination to fathom. Stars are rammed together much more than in our part of the galaxy. Many Astronomers believe stars close to the nucleus are separated by less than two trillion miles, and as they whirl around the galaxy's center at breakneck stellar speed, star collisions are commonplace. What's causing the stellar chaos is a giant black hole at the exact center of the Milky Way that's more than 1 million times the sun's mass made up of the corpses of dead stars that have been swallowed in the galactic abyss.Despite the dark clouds hiding most of the downtown Milky Way, there's a lot of cool stuff to see in and around the Sagittarius teapot.If it's dark enough from where you're viewing, you might even see a "puff of steam" with your naked eye just about at the teapot's spout. That's the Lagoon Nebula, a massive cloud of hydrogen gas being lit up by stars within like a giant fluorescent lamp. The nebula is more than 4,000 light-years away, or if you prefer, 26,000 billion miles from your backyard. As far as that is, that's celestial chicken feed compared the center of our galaxy, which is more than 25,000 light-years away. I would put that in miles, but newspaper ink gets a little expensive.With larger telescopes, there's a lot of other star clusters and nebulae to peruse in and around the arrow-shooting centaur. There are amateur astronomy and celestial photography targets like the Eagle Nebula, the Trifid Nebula, the Omega Nebula and many more. Also, At last count, astronomers know of 16 stars in Sagittarius that have planets circling them, more than any other constellation.The teapot is boiling over!Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book "Pennsylvania Starwatch," available at bookstores and at his website www.lynchandthestars.com.
