Starwatch 0804

Before I delve into those three summer stargazing delights, I’m delighted to tell you that one of the year's best meteor showers has begun! The peak of the Perseids is next weekend, and the shower will continue over Butler into the following week.

Look for Perseid meteors or “shooting stars” racing across the sky. The best time for viewing is in the hours after midnight to just before the start of morning twilight.

Lie back on the ground or in a reclining lawn chair and roll your eyes all around the sky to catch them. I’ll have much more on the Perseid meteors next week in Starwatch.

Like it or not, you’re being stalked every clear night by a pair of eyes. In most stargazing circles, they’re called the “cat’s eyes.” They’re certainly not all that bright, but they are a lot of fun to look for in the classic summer constellation Scorpius the scorpion in the low southern sky as evening begins.

Scorpius is one of my favorite constellations because it’s one of the few that actually looks like what it’s supposed to be. The only problem is that the great scorpion never gets all that high in our Pennsylvania sky. The tail barely gets above our horizon. Stargazers in the southern half of the U.S. have a better view of Scorpius as the celestial beast takes a much higher track in the sky. I highly recommend checking out Scorpius if you’re down south in the summer.

Nonetheless, even in more northern latitudes, Scorpius is still a great attraction in the summer sky. It lies in the Milky Way band that runs from the northern to the southern horizon. The band is made of the combined light of billions of distant stars in the thicker plane of our home galaxy. Scorpius lies nearly in the direction of the center of our galaxy, so the Milky Way band is a little brighter there, especially if you see it in the dark countryside on a moonless night.

The brightest star in Scorpius is Antares at the heart of the beast. It’s the brightest star in that part of the heavens. Antares has a definite reddish hue. That’s because it’s a red supergiant star. Antares is cooler than our sun, with a surface temperature of close to 6,000 F, compared to 10,000 F. The red hue of Antares is also reflected in its name. It comes from ancient Greek, which roughly translates to English as “rival of Ares,” which is the Greek name for the planet Mars.

To the right of Antares, you’ll see three dimmer stars in a vertical row that make up the Scorpion’s head. Look for the beast's long-curved tail to the lower left of Antares.

The tail of Scorpius is the home of the dimmer pair of cat’s eyes. They are made up of two moderately bright stars very close together, Shaula and Lesath, and mark the scorpion's stinger. Spotting the cat’s eyes is challenging because they’re very low in the sky, super close to the horizon. Trees can easily block your view, so you have to look for them in a location where you can see all the way down to the horizon.

Honestly, with the naked eye, these two stars aren’t really all that impressive and aren’t all that much better with a telescope. Despite that, they are a couple of really impressive stars. Shaula, a little over 700 light-years away, is the brighter of these two cat eyes. It’s at least 6 million miles wide. Its surface temperature is over 40,000 F, more than five times as hot as the sun, and it kicks out more than 35,000 times more light than our home star. Lesath, the dimmer right eye of the cat, is almost as impressive as Shaula. It’s nearly 600 light years away, slightly smaller, cooler, and dimmer, but still a mighty star in our Milky Way Galaxy.

Have a stare-down with the cat’s eyes!

Mike Lynch is an amateur astronomer and retired broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and adventurepublications.net. Contact him at mikewlynch@comcast.net.