By Deane Morrison

University of Minnesota

Star watchers have good reasons—besides the usual one—to celebrate on July 4. First, we get a new moon, which means we can watch stars and planets at any time of night without lunar interference.

If you’re out after nightfall, don’t miss the S-shaped form of Scorpius low in the south, with Saturn (to the left) and Mars bracketing the scorpion. Note the reddish glow of Antares, the heart of the scorpion, below the ringed planet. Mars is now moving toward Saturn and will pass the ringed planet in August.

In the northwest, find the Big Dipper and extend the arc of its handle to see magnificent Arcturus, a star that’s rapidly plunging through the disk of our Milky Way galaxy. Arcturus sits near the “tail” of kite-shaped Bootes, the herdsman. Just east of Bootes, Corona Borealis, the northern crown, hangs like a necklace. Again to the east, Hercules, with its signature hourglass of stars, kneels upside down. A star chart will help in finding all these jewels, along with Ursa Major, the constellation that contains the Big Dipper.

Also on the 4th, Earth reaches aphelion, the farthest point from the sun in its orbit. At that moment we’ll be 94.5 million miles from the sun and traveling at our lowest speed.

July’s full moon arrives at 5:56 p.m. on the 19th. It rises less than three hours later, so it will look very round and beautiful. Algonquin Indians named this the full thunder moon, as thunderstorms are now so frequent.

July also brings us the dog days of summer. In ancient times, these days of intense heat were thought to come from the combined furnaces of the sun and Sirius, the brilliant Dog Star, as they traveled together across the summer sky. We can’t see Sirius now, but in winter it reigns as the brightest star in the night sky.

You may have heard in the news that an international team of researchers calculated that worldwide, only about a third of people live in areas where light pollution doesn’t keep them from seeing the Milky Way. In North America, however, the figure is even lower: A mere 20 percent of people can see the Milky Way from where they live. So if you live in or near an area that’s far from bright city lights, you’re among the lucky few. When you go out to watch the stars and planets, take some binoculars and explore the wonderfully rich starfields the Milky Way has to offer.

The University of Minnesota offers public viewings of the night sky at its Duluth and Twin Cities campuses. For more information and viewing schedules, see:

Duluth, Marshall W. Alworth Planetarium: www.d.umn.edu/planet

Twin Cities, Minnesota Institute for Astrophysics (during fall and spring semesters).