A constellation with a double identity and one week to go on the great solar eclipse
Among the gang of 88 constellations seen from Earth, with about 66 of them available in southwest Minnesota, there are eight bird constellations. I suppose that only figures since birds spend a lot of time in the skies. The largest and brightest bird constellation seen around here is Cygnus the Swan. On these mid-August evenings Cygnus is flying high in the eastern heavens.
The bright star at the tail of the high-flying swan is Deneb, one of the stars of the “Summer Triangle” in the eastern to overhead sky. The other Summer Triangle stars are Vega and Altair, the brightest stars of their respective constellations, Lyra the Harp and Aquila the Eagle. Just look for the three brightest stars you can see in that neighborhood of the sky and that’s it!
If you face south as you gaze up at the Summer Triangle, the star on the left corner of the triangle is Deneb. It’s the dimmest of the triangle but it’s certainly not diminutive. Just the opposite, it’s a tremendously gargantuan star at least 1,500 light- years away and possibly 3,000 light-years distant. Just one light year equals almost 6 trillion miles. The light we see from Deneb these summer evenings left that star around 500 A.D. and maybe as long ago as 1000 B.C. Theoretically it could explode tonight and our great-great- great-great……grandkids may not see that explosion until 5000 A.D.
The very fact that we can see Deneb at that distance with our naked eyes says that it must be one big star. According to the latest data, Deneb is 257 million miles in diameter and is estimated to emit nearly 400,000 times more light than our sun. If Deneb was at the same distance of as Vega, Deneb’s neighbor in the Summer Triangle, Deneb would be almost as bright as our full moon. We would easily see Deneb in the daytime.
Cygnus the Swan is also known by its other identity, the Northern Cross. In fact, it’s much easier to see the Northern Cross before looking for the Swan. Deneb sits at the head of the cross and if you’re facing south the cross will be overhead leaning to the left. At the foot of the cross is the not-so-impressive star Albireo, at least not impressive to the naked eye. However, with a small telescope you’ll see Albireo is not just one star, but a beautiful pair of stars, one gold and the other blue. It’s one of the best double stars of the sky.
The Greek mythology about Cygnus is a sad one, with just a bit of a happy ending. Apollo was one of the most important gods of Mount Olympus, the god of the sun. Day after day he guided the flatbed chariot with the sun fixed to it, pulled gallantly across the sky by a fleet of flying white horses. Apollo loved his job and was rewarded handsomely by Zeus, the king of the gods. Apollo also had a great family with many children.
One of the sun god’s kids was Phaethon, who at 10 years old idolized his dad and very much wanted to eventually take over the reins of the sun chariot when Apollo retired. Phaethon begged and begged his dad to let him take the sun chariot for a ride but Apollo said no. He was just too young. Phaethon, however, was convinced he could handle it. One morning temptation set in, and disaster quickly followed.
Phaethon was up way early that morning and snuck into the sun chariot hangar. This was his chance! He climbed into the driver’s seat and before he knew it, he shot out of the hangar into the wild blue yonder! Truth be told, Phaethon was being an excellent pilot.
His confidence got the best of him though, zigzagging and pulling celestial wheelies with the chariot. He soon lost control and the sun chariot was on its way to a horrible crash. From Mount Olympus Zeus saw what was happening and took immediate action. He thought some scoundrel had stolen the chariot, not knowing it was his grandson in the driver’s seat. He shouted down to Apollo, waking him up, and then shot a lightning bolt at Phaethon, spearing him out of the driver’s seat and sending him on the way to a fatal plunge. With the sun chariot totally out of control and within minutes of crashing, Apollo quickly borrowed his sister Diana’s moon chariot and soon had the sun chariot under control.
Phaethon swan dived into the river Po and drowned. Other gods recognized the body when it surfaced and took great pity on him. At that instant they magically transformed his body into the beautiful constellation we see as the heavenly swan.
ONE WEEK TO GO TO THE SOLAR ECLIPSE!
Unless you’ve been on another planet, you’ve heard about the total solar eclipse, a momentous celestial happening. In Marshall it will be a 88 percent partial eclipse, but there will be a total eclipse from coast to coast, from Oregon to Nebraska to Missouri, and all the way down to the coast of South Carolina. If at all possible you should travel to see it, at least that’s my advice. Watch the weather and try to be flexible with where in the band you choose to view the eclipse. A great cloud cover forecaster is clearskyclock.com. A great app and website for more eclipse information is eclipse2017.org. Again, I can’t say this enough, you must have eye protection like special eclipse glasses to watch any part of an eclipse. Protect your eyes! I’ll have much more on the eclipse next week!
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications available at bookstores at http://www.adventurepublications.net.