Athena's Web Weekly Column

Week of Oct 6th - Oct 12th, 2006

Pleiades Rising

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  In the early evening hours of October, shortly after twilight has danced her final round, the Pleiades begin to rise, climbing slowly higher in the eastern sky as the season unfolds.
Pleiades Rising

Pleiades Rising

At the opening of the 20th century, Richard Hinckley Allen wrote that this tiny cluster of stars, have "everywhere been among the most noted objects in the history, poetry and mythology of the heavens... All literature contains frequent allusions to them, and in late years they probably have been more attentively and scientifically studied than any other group." While our focus may have changed somewhat in the post-Hubble world, the Pleiades continue to be a famous and noteworthy legendary grouping of stars.

  While the Pleiades currently cluster around zero degrees of Gemini, precession has carried them a long ways over the years. They were among the first stars to be mentioned in astronomical literature, appearing in Chinese annals of 2357 BC as Alcyone hugged the vernal equinox (zero degrees of Aries). Because the Pleiades are a cluster, each of the many stars of the group cross at different times. The first star in the series would have been Atlas, the last Electra, with Alcyone falling in between. Measured by longitudinal conjunction, Atlas aligned with the vernal equinox about 2363 BC, with Alcyone crossing in 2336 BC and Electra around 2295 BC. By Right Ascension Midheaven (RAMC), the vernal equinox would have aligned with these same stars in 2253 BC, 2220 BC and 2175 BC, or about a century later. The Pleiades are located just north of the ecliptic, and so the difference in the two ways of measuring spring to determine it's beginning are not far apart when you consider that this is part of a 26,000 year cycle. As the Sun aligned with the vernal equinox over the stars of the Pleiades, many different ancient civilizations noted it as the mark of the start of their New Year.

Pleiades stars

The sisters and parents of the Pleiades

  As a Persian lunar station they were called Perv or Perven, terms derived from Peru, the 'Begetters,' as beginning all things, "probably with reference to their beginning the year." (Allen)

  The name Pleiades was also written as Pliades or, in the singular, Plias, from plein, "to sail", for the helical rising of the group in May marked the opening of navigation for the Greeks, as its setting in the late autumn did its close. Some poets claimed they were pigeons flying (fleeing) from Orion the Hunter, who rises after the Pleiades and seems to chase them across the sky through the night. Pigeons were also released at the beginning of the nautical year with the helical rising, linking these two through this annual celebration. Both Milton and Apollodorus felt that the stars of the Pleiades had a sensual nature. From the Astronomica by Apollodorus,

  "...sisters who vie with each other's radiance. Beneath their influence devotees of Bacchus and Venus (celebrants) are born into the kindly light, and people whose insouciance runs free at feasts and banquets and who strive to provoke sweet mirth with biting wit."

  While Milton penned it thus: "...the gray Dawn and the Pleiades before him danc'd, Shedding sweet influence..."

Kuiper Belt

Kuiper Belt

  You can even find the Pleiades on the highways nowadays. These seven stars are the logo and interpretation of the Japanese name Subaru.

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