This is the time of year I pack in as much stargazing and astrophotography as I can. Evening twilight in the Northwest ends later and later each day. Time is running out for prime-time backyard astronomy.
In the two to three hours before morning twilight, you can enjoy the same constellations and celestial goodies that you see on summer evenings, but more clearly now without the humidity or haze in the air.
Look for two bright open clusters of stars nearly overhead, at the fading end of evening twilight.
I know you’ll recognize one of them, the Pleiades, right away. Even in heavy city lighting this cluster of stars is easy to find hanging near the overhead zenith. It looks like a mini Little Dipper. Tonight the first quarter moon will parked right next to Pleiades in a nice celestial hug.
The Pleiades is also known as the Seven Little Sisters after the daughters of the old Titan god Atlas. According to Greek mythology, the Titan gods preceded the gods of Mount Olympus.
As the story goes, when Zeus and the rest of the newer Mount Olympus gang of gods knocked off the old Titan deities in a tumultuous war, they punished Atlas by forcing him to hoist up the entire world on his weary shoulders for all eternity.
The brightest stars that make up the Pleiades cluster are all named after the daughters of Atlas. They are Maia, Electra, Alcyone, Taygete, Asterope, Celaeno and Merope. Pleione, Atlas’ first wife and the mother of the sisters is also represented by a dimmer star in the Pleiades.
Most people only see six of the seven “naked eye” stars in the Pleiades. It’s thought by many astronomers that Pleione may have been a lot brighter way back when. One theory is that Pleione is what’s known as a shell star, complicated stars that go through many cycles of brightening and dimming over millions of years. Currently Pleione is the on downward side of brightness.
Through just an ordinary pair of binoculars or a small telescope you can see that there are many more stars in the Pleiades than just the six or seven shiners. Astronomically they’re all siblings, born out of the same birth cloud of hydrogen about a hundred million years ago.
That makes them young compared to most stars in our sky. This cluster that’s more than 400 light-years away will eventually get pulled apart by the gravitational tug from other stars in our Milky Way Galaxy as it hurls through space at nearly 25,000 miles an hour.
There’s another open star cluster in our overhead neighborhood that is related in lore to the Pleiades. It’s the V-shaped Hyades star cluster that actually outlines the snout of the constellation Taurus the Bull. The Hyades is a 7-million-year-young cluster of stars that’s just 150 light-years away, making it the second closest cluster of stellar youth to Earth.
The only ones closer are the stars that make up the constellation Ursa Major, the Big Bear. Just one light-year equals close to 6 trillion miles.
Among the moderately bright stars of the Hyades is a brighter reddish star, Aldebaran, the angry eye of Taurus the Bull.
Aldebaran is located in the foreground of the Hyades cluster, about 65 light-years away.
Get a good look at the Hyades because it’s going away. Astronomers have discovered that it’s rapidly moving away from Earth. In about 50 million years it will shrink to the size of our moon.
Mike Lynch is an astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, “Washington Starwatch,” available at bookstores and at his Web site www.lynchandthestars.com.
The Everett Astronomical Society welcomes new members. Go to www.everettastro.org/.
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