The Pleiades star cluster rises between the trees in the northeastern sky on a recent night. The attractive group comes up around 10 p.m. local time and is high in the east around midnight. Photo: Bob King
What’s lovelier on a September night than watching the Pleiades rise in the east? Whether you’re alone or in a group, when the “seven sisters” appear, everyone stops what they’re doing for a minute to admire this most beautiful star cluster. When I’m at a star party, someone inevitably calls out their first appearance like a courier announcing Caesar’s return to Rome. Yes, they’re that big of a deal.
The Pleiades represent the seven daughters of Atlas and Pleione, which are also members of the dipper-shaped cluster. Asterope and Calaeno usually require binoculars to see. Credit: John Lanoue
The name Pleiades (PLEE-uh-deez) comes from ancient Greek myth. Also called the Seven Sisters Cluster, the stars represent the seven daughters of the titan Atlas and sea-nymph Pleione. The origin of the name is uncertain but may be related to the word plein ( ‘to sail’), since the stars’ conjunction with the sun in spring and rising at sunset in fall marked the beginning and end of the sailing season in ancient Greece. Other possible origins include peleiades (‘flock of doves’) which is consistent with the story of Zeus turning the sisters into doves as they were pursued by Orion.
An interpretation of the Pleiades from a 10th century Anglo-Saxon manuscript called a codex (Codex Vossianus 79).
Being a compact group of bright stars quite unlike any other in the sky, the Pleiades have figured prominently in the sky lore of many cultures. Most people I know refer to the cluster as a “little dipper” or miniature version of the Big Dipper. My eye sees a shopping cart or baby stroller. Here’s just a small sampling of how others have interpreted their appearance:
* Japan – a strainer or dabs of paint on the sky
* Celtic mythology – associated with a fall festival of the dead since the cluster rose in the east as the sun disappeared in the west in that season
* Maya Indians – a rattlesnake’s tail
* Mono people (Native Americans) of California – Six wives who loved onions more than their husbands and who now live happily in the sky.
* Babylonians – Mul Mul or “star of stars”
* Maori of New Zealand – “Matariki” or little eyes
* Czech Republic – “Kuratka” or many small, young chickens
It’s their sheer compactness that delights the eye. They’re gathered so close together they seem enveloped in a fuzzy cocoon that further adds to their appeal. Poet Alfred Lord Tennyson said it best in his poem Locksley Hall:
“Many a night from yonder ivied casement, ere I went to rest,
Did I look on great Orion sloping slowly to the West.
Many a night I saw the Pleiads, rising thro’ the mellow shade,
Glitter like a swarm of fire-flies tangled in a silver braid.”
The Pleiades cluster contains about 1000 stars. Its core – what we see with the naked eye – is about 8 light years across or twice the distance to Alpha Centauri. Most of its stars are young, hot and blue. The cloudiness around the stars is starlight reflecting off a dust cloud through which the cluster is currently passing. Credit: NASA
My old friend Roy would recite those famous lines on winter nights observing together from my old suburban Chicago neighborhood. I have many memories of good times with the Pleiades and many associations, too. They’re always a reminder of the coming winter when they sail high across the southern sky. In mid-September the sisters make their first appearance in the east around 10 o’clock.; by mid-October they’re up at 8.
The Pleiades are exactly what they appear to be – a real, physically connected cluster of stars. They coalesced from a cloud of dust and gas about 100 million years ago smack in the middle between the appearance of the first flowering plants and disappearance of the dinosaurs. Located about 440 light years from the Earth, the light you see tonight left the cluster in the late 1500s, some 30 years before Galileo first pointed his telescope at them. His sketch shows many more stars that you can see with the naked eye alone.
Sketches of the Pleiades by Galileo. Notice the line of stars stretching to the left of the “dipper”.
At a casual glance, you’ll probably see just five or six stars, but if you peer closely, the seventh, Pleione, will materialize. The real fun starts when you avert your vision and look around rather than directly at the cluster. A smattering of faint stars will suddenly pop into view boosting your total to 8, 10, 14??
Give it a try, then beam in on them with binoculars. Whoa! Instead of seven, you’ll see many dozens, including a most attractive stream of stars shown so well in Galileo’s drawing.
I wish you smooth sailing with the daughters of the night.