During the morning hours of Sunday, Sept. 22, skywatchers across much of the western US will be able to watch as a waning gibbous moon — 75 percent illuminated by the sun — crosses in front of probably the most noteworthy and popular of all the star clusters in the sky: the Pleiades. The Pleiades cluster (also known as Messier 45 or M45) can be found low in the east-northeast part of the sky this week around 10 p.
m. local daylight time. By 4:30 a.
m., they are literally soaring nearly overhead, high in the south. Sunday's event, known to astronomers as an occultation, is part of a series of such events of the moon engaging with this famous group of stars that will continue for the next few years.
We will have more to say about this upcoming event a bit later, but first let's talk about the Pleiades themselves. A storied star pattern Few star figures are as familiar as the Pleiades, known also as the Seven Sisters. Anyone having difficulty in recognizing various stars and constellations should start with the Pleiades, because there is nothing else like them in the sky and nobody can look very long at the heavens on a winter night without noticing them and wondering what they are.
Located in the zodiacal constellation of Taurus the Bull , they mark the bull's shoulder. To the average eye, this group looks at first like a shimmering little cloud of light. But further examination, aided by good eyesight, will reveal a tight knot of 6 or 7 stars, though some have recorded more .