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Seven Sisters Rising

by Geoff Chester, USNO Public Affairs | 31 October 2023

by Geoff Chester, USNO Public Affairs | 31 October 2023

Messier 45, The Pleiades star cluster in Taurus, imaged 2017 December 17
at Great Meadow, Old Tavern, Virginia with an Explore Scientific 10.2-cm (4-inch) f/6.5 refractor
and a Canon EOS Rebel T2i DSLR

The Moon begins the week carving an arc through the winter constellations in the morning sky.  Last Quarter occurs on the 5th at 3:37 am Eastern Standard Time.  Look for Luna high above the bright stars of Orion before dawn on the mornings of the 1st and 2nd.  The next morning she forms an attractive triangle with the bright stars Castor and Pollux in Gemini.  By the end of the week she passes through the stars of Leo, the Lion and draws a bead on Venus.

The annual fall ritual of setting our clocks back by one hour occurs at 2:00 am on the morning of the 5th.  The most dramatic effect of this is that most of us no longer awake before the Sun, and it’s dark by the time we sit down to the evening’s dinner.  This annual exercise has been a bone of contention for well over 100 years, with staunch defenders in both “standard” and “daylight” camps.  Its origins date back to the late 19th Century, but it was first applied during World War I as a means of keeping munitions factories open longer for day-shift workers.  Here in America, it has been an on-again-off-again proposition since 1918 until it was finally enshrined in U.S. Code in 1966.  Our current clock change rules date to the Energy Policy Act of 2005.  In case you’re wondering, as an astronomer I prefer standard time!

The passing of Halloween kicks off the observance of the winter holidays, and in many traditions marked the beginning of the winter season.  One of the sure signs of the approaching colder weather is the appearance of a small knot of stars that rises at the end of evening twilight.  Despite its diminutive size, the Pleiades star cluster holds a prominent place in the sky lore of just about every culture that has left us records.  One of the earliest mentions of the asterism dates to a Chinese manuscript from the year 2537 BCE.  Their midnight culmination has been linked to the destruction of the mythical Atlantis, which many now associate with the colossal explosion of the Thera volcano circa 1450 BCE.  Their appearance at sunset signaled the onset of early winter gales for early mariners in the Mediterranean, and they have long been a portent of weather for sailors throughout the Northern Hemisphere.  Many Mesoamerican cultures worshipped the appearance of the cluster, and the vast, ancient city of Teotihuacán in Mexico was built with a number of axes aligned to the Pleiades.  One of my favorite legends comes from the Kiowa tribe of Native Americans.  They saw the stars as seven Indian maidens who were cornered by giant bears.  The Great Spirit pulled the ground that they were huddled on up into the sky, creating the dramatic formation we know as the Devil’s Tower in Wyoming.  The striations on the sides of the tower are the claw marks of the frustrated bears!

The Pleiades are a true star cluster, one of the youngest and closest to the solar system.  Located about 444 light years from us, and, while some six to twelve of its members can be see with the naked eye, there are at least 1000 known stars among its ranks.  Its brightest stars, named for the seven daughters of Atlas in Greek mythology, shine with some 2000 times the luminosity of the Sun.  They are relative newcomers to the neighborhood, having formed some 100 million years ago.  Long-exposure images show them enveloped by wispy clouds of luminosity.  These are the remnants of the proto-stellar nebula that the stars formed from.  They are one of my favorite sights in a low-power telescope, easily seen from urban skies but spectacular when viewed from dark locations.  The brightest members glow with an icy blue color set in the diffuse haze of their surrounding nebulosity.  Dozens of fainter stars fill the background behind the brighter members.

Saturn is now best placed for viewing in the early evening sky.  You will find him in the southern sky shortly after sunset.  He crosses the meridian at the end of evening twilight, offering his best views for the small telescope.  The ringed planet reaches the second stationary point of this year’s apparition on the 4th, stopping his apparent westward motion before slowly resuming his eastward trek along the ecliptic.

Jupiter reaches opposition on the 3rd.  This is the moment when the giant planet is opposite the Sun in the sky, rising at local sunset and setting at local sunrise.  As Saturn heads toward the western horizon, Old Jove climbs higher in the east, his bright glow dominating the sparse star fields of Pisces and Aries.  For the urban sky watcher, Jupiter offers an easy target for the telescope that changes from night to night.  The ever-changing configurations of his four bright Galilean moons and the contortions of his surface cloud belts beckon for hours of nightly viewing.

Venus continues to grab your attention in the pre-dawn sky.  The dazzling planet is now drifting between the rising spring constellations of Leo, the Lion, and Virgo, goddess of the harvest.  Over the course of the week the waning Moon will draw closer to Venus; next week the two will experience a close conjunction. 


Commander, Naval Meteorology and Oceanography Command | 1100 Balch Blvd. | Stennis Space Center, Mississippi 39529

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