What’s Up in the Sky – June, 2013
A Variety of Sights in June’s Sky
After the last Ice Age, Africa’s Sahara desert was green and fertile and the climate supported an abundance of wildlife that attracted huntsmen, and later herdsmen. These people recorded scenes of life in rock paintings of great beauty. Surely, while tending their flocks under pristine skies with diamond stars, they looked to the heavens and saw herdsmen.
One of springtime’s best constellations, Bootes (boo-OH-teez), is often depicted as a herdsman and is easily found this time of year. Find the Big Dipper high in the southwest and follow the arc of the handle away from the bowl down to the bright star Arcturus (“follow the arc to Arcturus”). Above it lie five stars in the shape of a leaning house which, along with Arcturus, form the main body of the constellation.
The name “Arcturus” means guardian of the bear so we have a herdsman driving a bear (Ursa Major) through the sky. I guess a bear is more exciting than a cow. Arcturus is also notable for being the first star to be observed in the daylight with a telescope. And that was in 1635.
Scenes such as those depicted in the Saharan rock paintings suggest that Bootes is one of the oldest constellations and was even mentioned in Homer’s Odyssey of the 8th century B.C.
Now look just to the east (left) of Bootes for a circlet of stars forming a small bowl. This is Corona Borealis, the Northern Crown. Another ancient constellation, it was known to the Arabs as a broken dish, the Greeks called it a wreath, and to the Australian aborigines it represented a boomerang.
Corona Borealis is associated with a number of mythological legends. It was once known as the Crown of Ariadne, the heroine who saved Theseus from the minotaur in the maze on Crete. Later she married the god Bacchus who had given her a magnificent jeweled crown. When she died, he honored her by putting her crown in the heavens.
The brightest star in the constellation, Gemma, Latin for “gem”. It is also sometimes known as “Alphecca” which is derived from an Arabic root meaning “broken” perhaps referring to the broken ring of stars.
Then there is T Corona, also called the Blaze Star. Normally inconspicuous at magnitude 10, in 1866 and again in 1946 it flared up to be as bright as Gemma. We call such stars “recurrent novae”.
So, from a herdsman driving a bear to a crown of jewels, there is much to enjoy up in the sky.