Spooky Dark Nights of October

by Rod Kennedy

October is the time for ghosts and ghouls and things that go bump in the night.  This is the season that ancient Celts knew as Samhain (pronounced Sawan) and was the traditional start of winter.  This made it a dark time of death and a time when the walls between the real world and the spirit world was thin.  To us, this seems like ancient superstition.  Yet the night skies of October will be quite dark, perfect for the holiday at the end.

October’s skies are dark for a number of reasons. First, there are very few bright stars visible in October.  The bright stars of Scorpius and Sagittarius have vacated the southern skies, Arcturus and Spica are long gone in the West, and the bright stars of winter don’t rise in the East until well after midnight.  Only the 3 stars of the summer triangle remain to light up the night.  The stars Vega, Altair and Deneb form the summer triangle; an asterism that is visible from late spring through fall.  Each of them is the brightest star in a true constellation.  Vega is in Lyra the Harp, Altair in Aquila the Eagle, and Deneb is in Cygnus the Swan.  These constellations are slightly West of directly overhead throughout October.

Slightly to the East of the Summer Triangle is Pegasus.  The 4 brightest stars of Pegasus form an asterism known as the Great Square, but are almost too dim to be seen in the light polluted skies of any city.  Further East and North of Pegasus is Perseus.  Perseus is easy to spot if you look for the “fish-hook” or J shape.  However, like Pegasus, Perseus is almost lost unless you’re far from city lights.

The only other bright beacons of October are members of our own solar system.  The most obvious will be the planet Jupiter.  Jupiter is the brightest object high in the Southeast.  There are no bright stars in the vicinity, so it is easy to pick out.  The moon is also very bright in the first half of the month.  The moon reaches first quarter on the evening of the 14th, and will be full on the night of the 23rd.  However, by Halloween the 3rd quarter moon will not be visible until after midnight when it rises in the East.

Skywatchers looking for something more exotic than stars and planets should be ready on the night of October 20th.  Comet 103P/Hartley 2 will make its closest approach to earth on this night and should be dimly visible to naked eye observers under dark skies.  On the evening of the 20th the comet will be only 11 million miles from Earth.  The odd thing about this particular comet is that it appears green through telescopes or binoculars.  To find Comet 103P/Hartley 2 look Northeast in the constellation Cassiopeia.

Our ancient ancestors saw  October as a dark time.  For them the darkness was the rapid approach of winter, and the death of the world they saw around them.  While we no longer fear winter as our ancestors did, October remains a dark month.  Not because of fear, but for a simple lack of many bright lights in the night sky.

October 2010 Chart

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