Bootes the Herdsman

High overhead as darkness falls in the Northern Hemisphere these early summer evenings shines a lone, bright orange-hued star. Just go out and look almost straight up around 9 o'clock; you can't miss it. This star is Arcturus, the luminary of the constellation Bootes the Herdsman.

If you live in a suburban location, you can probably just make out the constellation's star pattern. It looks like an ice-cream cone with bright Arcturus at the cone's apex and the ice-cream end pointing more or less toward the northeast. Martha Evans Martin, in her book The Friendly Stars, was not much impressed with Bootes, however. 'It is a very pretty constellation,' she writes, 'and of some astronomical interest, but it is not remarkable to the ordinary view except for its one brilliant star.'

What it may lack in aesthetic beauty, however, it more than makes up for in heritage. Bootes, like Ursa Major, is another of one of our oldest constellations, and as a result, its mythology is considerably rich and varied. The name is a derivation of the Sumerian Riv-but-sane, the Man Who Drives the Great Cart. It is associated with the farmer who plows his fields in the spring (when Bootes first appears). The Romans referred to Bootes as the Herdsman of the Septemtriones, the seven oxen, which are represented by the seven stars of the Great Cart, known today as the Big Dipper.

According to one Greek legend, Bootes is actually Arcas, the son of Zeus and the nymph Callisto. Arcas suffered many hardships after being robbed of all his possessions. In order to make his living, he invented a plow that was drawn by two oxen. Like most mothers, Callisto was so proud of her son's resourcefulness she wanted to tell the whole world. She convinced Zeus to place her son in the sky together with his plow.

Giuseppe Maria Sesti, author of The Glorious Constellations, asserts that Bootes' mythological tree can be traced back 8,000 years, to a time when the constellations were in different positions in the sky. Over a period of several thousand years, precession, the wobble in Earth's rotational axis, noticeably changes the positions of the stars with respect to the north celestial pole. Since all the stars in the Northern Hemisphere appear to revolve around the north celestial pole, a star located near the pole is of considerable importance (as Polaris is today). It also stands to reason that stars near the pole would also be assigned some important role.

If we look back in time to where the north celestial pole was nearly 7,000 years ago, around 5000 b.c., we find it some 12° north of the head of Bootes. Moreover, with the celestial sphere skewed around so, the constellation would have been seen by the people of that time as standing upright on the northern horizon at midnight on the summer solstice, apparently holding up the vault of the heavens near the point of the (then) north celestial pole. Sesti believes that the only mythological figure worthy of this important position was Atlas the Titan. Bootes'

right arm, arched above his head in support of the sky, may have consisted of the semicircle of stars known today as Corona Borealis.

The gradual movement of the north celestial pole among the stars has since shifted the spotlight awayfrom Bootes, forcing the constellation to assume a more agrarian position in the sky. We'll have to wait nearly 19,000 years for Bootes to once again assume its classical pose as Atlas.

Skywatchers who have access to a telescope should look for M3, a rich, condensed globular cluster located about 12° northwest of Arcturus in the adjacent constellation Canes Venataci, the Hunting Dogs. It is one of the most beautiful globulars in the northern sky, next to M13 (see August 2 - 8). In binoculars it can just be seen as a fuzzy star.

May 17-23

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