Dining & Nightlife | Astronomy

According to consumer marketing data, the most popular Halloween costumes in 2005 were Spiderman, princesses, witches, vampires, Sponge Bob, Barbie, and Harry Potter. Yet, despite the astronomical significance of Halloween, there were no Galileos, astronomers or even a Hubble!

How is Halloween astronomically significant? The answer is that it falls halfway between the Autumnal Equinox and the Winter Solstice, on the last of the four Cross Quarter days of the Solar Calendar. A Cross Quarter day is a day midway between an Equinox and a Solstice. For pre-Christian Celts and traditional Japanese Shinto societies, Equinoxes and Solstices signaled the midpoints of the seasons while Cross-Quarter days marked their beginnings. This contrasts with our own calendar where each season begins with an Equinox or Solstice. Nevertheless, vestiges of ancient celebrations tied to seasonal transitions remain in that each Cross Quarter day continues to be associated with a holiday: Groundhog Day (February 2), May Day (May 1), Lammas Day (August 1) and, of course, Halloween (October 31) or, in Mexico and some other Spanish speaking countries, Los Dias de los Muertos (the Days of the Dead), which takes place in late October or early November.

Another Halloween factoid: Currently, the Pleiades reach their zenith in mid-November; in ancient times, however, the Pleiades rode highest around Halloween and were considered a harbinger of cataclysmic events, including the return of the dead, as were comets and eclipses. Finally, I would like to remind my readers that comet P-17 Holmes, which burst into brilliance on October 24, 2007, is now sometimes referred to as the “Halloween comet.”

This October, the full Moon falls on the 4th. Just two days later, Mercury reaches greatest western elongation. The fiery planet will rise 35 minutes before the Sun and will grace the morning sky throughout the month. A close conjunction of Venus and Saturn takes place on October 13 when the two planets will be only half a degree apart in the early morning sky. Also on the 13th, Jupiter’s westerly retrograde motion will cease and the gas giant will again begin it journey to the east against the backdrop of stars. Look for it near Capricorn, high in the evening sky.

The Moon is new on the 18th, hence the skies will be dark for viewing the Orionids. This meteor shower yields about 20 meteors every hour, although irregular bursts of greater activity are often observed. Look for the Orionids in the eastern skies any time between the 20th and 24th. Why not join us at Custer, which will be having a meteor party on Saturday, October 24, from 8pm until after midnight?

Finally, humanity’s fascination with the sky is the subject of the sixth annual conference on the “Inspiration of Astronomical Phenomena” to be held in Venice, Italy, from the 18th to the 23rd of October, 2009. It is a part of the International Year of Astronomy, 2009, that celebrates the 400th anniversary of Galileo’s first astronomical use of the telescope. The conference was organized jointly with the Vatican Observatory. For further details, check out http://www.astro.unipd.it/insap6. This event might make for an interesting trip.