Summer Skywatching: See the Clouds of the Milky Way
One of the greatest pleasures for summer stargazers is viewing the splendor of the Milky Way.
Despite the fact that we live in this vast island of billions of stars, most inhabitants of Earth have never seen the clouds of our Milky Way. The illuminated dust of the galaxy was a commonplace sight throughout most of human history, but the sight has been lost to the last few generations because of our desire to light up the night with artificial illumination.
The Milky Way is still there, but you need to make a special effort to see it. Interested observers need to find a location far from modern cities where, on a dark moonless night, the faint glow of our galaxy fills much of the night sky. Take 15 or 20 minutes to let your eyes become fully adapted to the dark, and then look south. [See amazing photos of the Milky Way]
At this time of year in the early evening, the core of the Milky Way galaxy looms just above the southern horizon. The actual core of our galaxy is blocked from our view by countless stars and clouds of gas and dust, but the overall glow shines through.
Because we are immersed in the Milky Way, its stars are all around us. In fact every star we see with the naked eye is within the Milky Way. But because we live on the outer reaches of its disk, the overall glow of the Milky Way forms a broad band all across the sky. Looking south, the midline of our galaxy is canted over about 65 degrees to the left, rising from the southern horizon to a point about two-thirds of the way to the zenith in the east.
The height of the eastern arch of the Milky Way is marked by the three bright stars of the “Summer Triangle”: Vega, Deneb, and Altair.
I particularly like to look at the Milky Way with low powered binoculars. I prefer the 7x50 or 10x50 sizes for portability and wide fields of view. I start at the “teapot” formed by the bright stars of Sagittarius, and slowly sweep upwards.
Just above the "spout" of the teapot are a couple of puffs of steam, actually two of the brightest nebulas in the sky, the Lagoon and Trifid nebulas. You’ve probably seen many colorful pictures of these, but our eyes can’t pick up the faint colors of the night sky, so they appear to us as faint white clouds.
Further above the “spout” are two more nebulas, the Eagle and the Omega. This last is my favorite, looking in a telescope like the Greek letter omega or a swan serenely swimming through the night sky; its alternate name is the Swan nebula.
All four of these nebulas are huge clouds of hydrogen gas in which new stars are being born. After the stars form, these newborn stars form what we call open clusters or galactic clusters. Many of these new star clusters are found in this part of the sky, such as the Wild Duck Cluster in the tiny but rich constellation of Scutum.
Just below the Eagle and Swan nebulas is an unusual object, the Sagittarius Star Cloud. The famous 18th century hunter of nebulae, Charles Messier, was fooled into thinking this was a gigantic star cluster, and gave it the number 24 in his catalog. Recently we have discovered that, rather than being a real object, this is actually a hole in the nearby arm of the Milky Way, a window through we see the huge numbers of stars inhabiting the next spiral arm inward towards the center of our galaxy, the Norma Arm.
The Milky Way is an astronomical treat, which can be enjoyed with the naked eye, with binoculars, or with telescopes of any size. It’s worth the trip out of town to see it.
Editor's Note: If you have an amazing night sky photo you'd like to share for a possible story or image gallery, please contact managing editor Tariq Malik at spacephotos@space.com.
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