Driftless Dark Skies: The Pleiades

November 2nd, 2016 by John Heasley

Fool: The reason why the seven stars are no more than seven is a pretty reason.

Lear:  Because they are not eight?

Fool: Yes, indeed: thou wouldst make a good fool.

photo from APOD

photo from APOD

November is an excellent month to discover the Seven Sisters, the Pleaides.  They rise in the east just after sunset, pass high overhead at midnight, and set in the west around sunrise.  With only your eyes, you should be able to see half a dozen bright stars very close together making a pattern like a little dipper or teacup.  With binoculars, you can see dozens of stars.  A large telescope reveals over a thousand stars.

All these stars are part of an open cluster, a collection of stars born together in the same cloud of interstellar gas and traveling together as they slowly disperse.  They are relatively young stars, just 100 million years old.  Our Sun is forty times their age.  Unlike our long-lived yellow star, the Pleiades are blue-white giants burning fast and dying young.  They are so prominent because they are in our stellar neighborhood with a distance of 440 light years.  The light we see in 2016 left the Pleaides left just four centuries ago when Shakespeare and Galileo were alive.  I love that Shakespeare had the Fool use the Pleaides to school King Lear who has grown old before he has grown wise.  And Galileo was the first to turn a telescope to the Pleaides to see dozens of stars formerly invisible.

Orion the Hunter rises shortly after the Pleiades.  I like to follow the three bright stars of his belt to the right to find the Pleaides.  Midway between Orion and the Pleiades, you can see the Hyades, another open star cluster.  The five bright stars of the Hyades are further apart than the Pleiades and form a “V” that is recognizable as the horns of Taurus the Bull.  This cluster is even closer, and we’re looking at light that left during the Civil War.  The Taurid meteors of November 4-5 will originate from this part of the sky.  You may see a few fireballs.  Watch for the nearly full moon passing through here on November 14.

The Celts used the November appearance of the Pleiades to mark their cross quarter festival of Samhain halfway between the autumnal equinox and winter solstice.  Samhain is the beginning of the New Year and was associated with death and mourning and a time when the boundary between the worlds of the living and the dead was not so firm.  Samhain, celebrated between sunset October 31 and sunset November 1, evolved into Halloween and the Christian feasts of All Saints and All Souls.  These are fine nights to watch the Pleaides traveling across our dark skies.

John Heasley is an astronomy educator and stargazer who enjoys connecting people with the cosmos. He volunteers with NASA/JPL as a Solar System Ambassador. For more information about stargazing in southwest WI, like Driftless Stargazing LLC on Facebook and find out whenever there’s something awesome happening in the skies. Driftless Dark Skies appears monthly in the Voice of the River Valley.

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