Right around 9 p.m., when enough evening twilight has been chased away, look in the low south-southwest sky and without too much trouble, you'll see a teapot hanging diagonally by its handle. A distinct triangle of three bright stars make up the spout on the lower right side and a trapezoid of four stars on the upper left make up the handle. In between and above the handle and the pot is a single star that marks the top of the teapot.
This celestial teapot is formally known as Sagittarius the Archer. By the way, I love the name of the upper-most right star in the handle. It's Nunki, pronounced Nun-Key. It's a star just over 225 light years away or a little more than 1,300 trillion miles away. If you were to put it side by side with our sun, it would be more than 3,000 times brighter.
According to Greek and Roman lore, the constellation Sagittarius is supposed to outline a half man, half horse flinging an arrow to the west. With a little imagination, you can sort of see that. The spout stars outline the bow with the tip of the arrow at the tip of the spout. The four stars of the handle would be the cocked elbow of the shooter. The top of the teapot would be his head.
Seeing Sagittarius as a teapot is so much easier and a lot more fun. The teapot nickname is relatively new to stargazing, evolving in the last 65 years or so.
If you're lucky enough to stargaze at Sagittarius "the teapot" in the glorious dark skies of the outer suburbs, or better yet the countryside, you'll easily see a band of light arching overhead, stretching all the way from roughly the northern horizon to the southern horizon. This is the famous Milky Way Band, the thickest part of our home galaxy. You can't help but notice that the Milky Way band runs right into Sagittarius. In fact, the center of our Milky Way Galaxy is right in the direction of the little teapot.
The downtown section of our home galaxy would appear a lot brighter in our sky, but there's a lot of obscuring interstellar gas and dust in the way. Some astronomers believe that if it weren't for all that gas and dust, the sky around Sagittarius would be brighter than the full moon.
Nonetheless, that part of the Milky Way band around Sagittarius is fairly bright anyway and loaded with a lot of fun stuff. It's a very busy part of the sky and, even with a small telescope or a pair of binoculars, you'll find many, many star clusters and nebulae. Some of the better ones include the Eagle Nebula (M16), the Swan Nebula (M17) and the Trifid Nebula (M20). The M numbers are Messier catalog numbers. The Messier catalog is made up of the brighter clusters, nebula and galaxies available in the night sky. A great website to find these in the night sky is stellarium.com.
Above the spout of the teapot is what almost looks like a puff of steam. That puff is astronomically known as M8, but is better known as the Lagoon Nebula, a bright emission nebula. It's one of the larger and brighter star factories we can see in the sky, and you don't need all that much of a souped-up of telescope to really check it out. This is a huge cloud of hydrogen that is the raw material to mass manufacture stars. The Lagoon is more than 5,000 light-years away and roughly 100 light-years in diameter. Just one light-year equals close to six trillion miles.
Stars form when denser pockets of hydrogen gas within the cloud gravitationally collapse, causing the temperatures in the core of these condensed balls to rise into the millions of degrees. When these horrendous temperatures are reached, the extremely complicated process of nuclear fusion begins and the ball of gas lights up into a star.
Even with a small telescope, you can see many new young single stars and clusters of stars and there are a lot more on the way in the Lagoon. These new young stars are very hot and are huge producers of ultraviolet radiation, and all this energy atomically energizes the surrounding hydrogen gas and causes it to glow like a fluorescent light. If your view is clear enough and your telescope strong enough, you may see strands of dark clouds across parts of the nebula. These are clouds of hydrogen gas that don't happen to have any bright new stars around them, so they appear to us in their raw form, dark.
Enjoy the Lagoon Nebula and all of the celestial treasures around Sagittarius. You're looking toward downtown Milky Way!
(Lynch is an amateur astronomer and author of the book, "Pennsylvania Starwatch.")