August will be an interesting month in the sky. For the first time in a long time, the evening sky will be almost devoid of planets. Mars will be a dying ember that will soon be lost in the twilight glow, and Saturn will not come into view until the late evening. With the absence of planets, it is a good time to visit the bright stars of summer. To make sure that we get our bearings, we will start with the Big Dipper. During August, it will hang diagonally in the northwestern sky. The front two stars of the bowl, called the Pointer Stars, point out the top of the bowl to Polaris, the North Star, about three fists to their right.

Once you have north established, turn left and face west. The brightest star there is Arcturus in the constellation Bootes (the Herdsman). I like to call Bootes the “Farmer in the Sky” because in Greek mythology, he was placed in the sky as a reward for inventing the plow. Arcturus is an orangish colored red giant that is swelling up as it reaches the end of its life. Its color is subtle and is best seen by comparing its color with other stars. If you look below or to the lower left of Arcturus as soon as it is dark, it can be compared to blueish-white Spica, the brightest star in Virgo (the Maiden).

Now turn and face east. High overhead will be Vega in the constellation Lyra (the Harp). Vega is a massive blueish-white star that is much more luminous and much hotter than the Sun. It is the top of the Summer Triangle of three bright stars that are in the sky all summer. Below or to the lower left of Vega is Deneb in the constellation Cygnus (the Swan). It is a white supergiant that is very massive, very hot, and very luminous star that is reaching the end of its life. It does not look extremely bright because it is very far from Earth – about 1,800 lightyears. Farther to Vega’s lower right is Altair in the constellation Aquila (the Eagle). Altair is a young white star that is about twice the size of our Sun, but is much more luminous.

Finally turn and face south. Look low in the sky for bright, reddish Antares in the constellation Scorpius (the Scorpion). Antares is translated as “rival of Ares (Mars)” because its red color closely matches that of Mars. Antares is a huge red supergiant that is reaching the end of its life. Its end-of-life throes have caused it to swell up to a massive size. If its center was at the center of the Sun, its outer reaches would extend to the asteroid belt. When Antares is at its highest and the sky is dark, the glowing band of the Milky Way will be at its best. It will rise up from Scorpius and Sagittarius (the Archer), immediately to its left, and pass high overhead and through the Summer Triangle before descending to the northern horizon near the “E” shaped constellation Cassiopeia (the Queen).

Observing Highlights

-Aug. 3: The Moon will be close below Antares, the bright red heart of Scorpius (the Scorpion).

-Aug. 11: Brilliant Venus and very bright Jupiter will pass each other in the predawn sky. Jupiter will be getting higher in the sky each day while Venus gets lower. They will be almost as close on the morning of the 12th.

-Aug. 12: The Perseid meteor shower will peak tonight and especially after midnight. Unfortunately, the bright Moon will obscure many meteors. They may be seen all over the sky, but they will seem to come from the northeastern sky near the constellation Perseus (the Hero). If you are observing, try to hide the Moon behind a building or tree.

-Aug. 26: The Moon will be to the left or lower left of Mars and to the lower right of Spica, the brightest star in Virgo (the Maiden) as night falls.

-Aug. 27: The Moon will be to the left of Spica, which represents a spike of wheat in the hand of Virgo (the Maiden).

-Aug. 30: Star Party sponsored by Grout Museum & Black Hawk Astronomy Club, Prairie Grove Park, Waterloo, 9-10:30 p.m.

-Aug. 31: The Moon will be to the lower right of Antares, the brightest star in Scorpius (the Scorpion). On the 31st, the Moon will have moved in its orbit and will be to the lower left of Antares. This will be the second time during August that the Moon has visited Antares. Since the Moon orbits the Earth in 27.3 days, it can pass the same star twice in a month.