What's in the Sky: Longer nights in August means more opportunity for stargazing

Nights are growing longer and days shorter. On Aug 1, we have 15 hours and 40 minutes of daylength. By the end of the month, that will have shrunk to 14 hours and 47 minutes, a difference of a bit more than an hour. The good news with darkness arriving earlier is that you don’t need to wait quite as long for full darkness (also known as the end of astronomical twilight). Full darkness at the start of August will be at about 10:43 p.m., but will be about an hour earlier by the end of the month, occurring at about 9:30 p.m.

A wonderful thing to view on August nights is our own galaxy — the Milky Way. We see the galaxy as a hazy band across the night sky, and it is best visible in August. Facing south on a moonless August night, the Milky Way soars high overhead. Look to the south, looking toward the “teapot” of the constellation Sagittarius, and you are looking toward the Milky Way’s center. Look straight overhead, and pick out the constellation Cygnus, the Swan, also known as the northern cross. The bright star Deneb is right in the middle of the Milky Way. Look to the north, and find the fainter Milky Way behind the “W” shaped constellation Cassiopeia. Marvel at the beauty of this river of stars!

The Milky Way is actually a spiral disc-shape, and we are within one of its disc’s arms. When we look along the plane disc, we see more stars than when we look 90 degrees from the disc’s plane. Even though we call the concentrated area of stars the “Milky Way,” in reality every star we see in the sky is within the galaxy. And we see only a small part of the galaxy, the stars closer to us. The galaxy is huge, some 100,000 light years from one end of the disc to the other. Since light travels some 186,000 miles a SECOND, we can see that the Milky Way is immense!

To best view the Milky Way, it’s best to pick a dark night, when the moon is not in the sky, and a dark site, with as little artificial light as possible. Also, let your eyes adapt to the darkness, by staying out of artificial light for a good 20 minutes. Finding a dark site is increasingly difficult with the ever-increasing amount of artificial light we live with nowadays. We are lucky in our area, with a lot of dark, rural locations and relatively small cities. Thanks to artificial lighting, people in most American cities are not able to easily view the galaxy we live in.

Our moon will be at the first-quarter stage as August begins. On the 3rd, the waxing gibbous moon will lie just to the left of the bright star Antares, low in the south in the evening sky, in the constellation Scorpius. Full moon comes on the 9th. On the 16th, the waning crescent moon will lie just to the right of the star cluster Pleiades, in the early morning sky. The moon will actually pass in front of the star cluster, a nice occultation. However, we’ll miss it, as the occultation will occur after sunrise. The thin, waxing crescent moon will return to the evening sky late in the month. Look for the moon between Mars and the bright star Spica, low in the west, after sunset on the 26th. The moon will be back in Scorpius at the end of the Month, just past first quarter.

Mars is technically still visible in August, although very close to the western horizon after sunset. The only other naked-eye visible planet in the month will be Saturn, which rises above the eastern evening horizon after about 10 p.m. late in the month. Jupiter and Venus are visible in the morning sky, in the east. On Aug. 11, Jupiter and Venus come close together in a nice conjunction.

Right after that conjunction, on Aug. 12 and 13, the Perseid meteor shower will peak. The moon, which will be about 80 percent illuminated, will make fewer meteors visible. Brighter meteors will be visible, and viewing the moon and the moonlit landscape on a warm summer evening can be quite pleasant.

Enjoy the night skies of August!