The arrival of September means many things to many people: harvest time, back-to-school, falling temperatures… but to me, September means the return of the Pleiades star cluster. The fall constellations are making their return to the evening sky, and the Pleiades star cluster in Taurus the Bull leads the way.
The Pleiades is known by a few other names, such as the Seven Sisters and M45. The Japanese call this stellar grouping “Subaru.” You may have noticed that the logo for the Subaru car company consists of six stars, not seven. When the cluster was first named hundreds of years ago, one of the stars was brighter than it is now, but today only six stars of the Seven Sisters are easily visible to the unaided eye.
Look through a pair of binoculars at the Pleiades and the question of whether there are six or seven stars becomes moot. Minimal magnification reveals that there are, in fact, hundreds of stars that make up the Pleiades cluster. The Pleiades is one of those astronomical objects that appears best through a pair of binoculars, because a telescope cannot capture the wide span of the cluster’s stars.
People unfamiliar with the sky who notice the Pleiades while stargazing sometimes mistake it for Ursa Minor, because its shape is reminiscent of the Little Dipper. However, the Pleiades cluster is on a much smaller scale than the constellation Ursa Minor.
The Pleiades is easy to find. In early September, the cluster rises in the late evening in the east-northeast. By the end of the month, the cluster rises just a couple hours after sunset. Trailing behind it are the V-shaped Hyades cluster that marks the head of Taurus the Bull, Castor and Pollux in Gemini the Twins, and the ever-recognizable belt in Orion.
September’s night sky brings much more than the arrival of the fall constellations; Jupiter’s moons will eclipse and occult one another, Saturn’s rings will disappear, and the equinox occurs.
Photo Credit: NASA/JPL/Space Science Institute
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Kelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She is currently the Feature Writer for Astronomy and Space at Suite101.com. You can follow her on Twitter at twitter.com/Astronomommy.