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Arcturus is a Halloween ghost of the summer sun

09oct31_430

Tonight is Oct 31, 2014

Moon Phase Courtesy U.S. Naval Observatory

Every Halloween – and a few days before and after – the brilliant star Arcturus sets at the same time and on the same spot on the west-northwest horizon as the summer sun. What’s more, this star rises at the same time and at the same place on the east-northeast horizon as the sun does during the dog days of summer.

At northerly latitudes, Arcturus sets in the west after sunset and rises in the east before sunrise

However, if you live in the Southern Hemisphere, you can’t see Arcturus right now. South of the equator, Arcturus sets at the same time and on the same place on the horizon as the winter sun. In other words, Arcturus sets before the sun and rises after the sun at southerly latitudes at this time of year.

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Cover of 'Star Arcturus, ghost of summer sun' coloring book

In the Northern Hemisphere – around Halloween – this brilliant pumpkin-colored star playacts as the ghost of the summer sun.

At mid-northern latitudes, Arcturus now sets about 2 hours after sunset and rises about 2 hours before sunrise.

By watching this star in the October evening chill, you can envision the absent summer sun radiating its extra hours of sunlight. Not till after dark does this star set, an echo of long summer afternoons. Similarly, Arcturus rises in the east before dawn, a phantom reminder of early morning daybreaks.

You can verify that you’re looking at Arcturus once the Big Dipper comes out. Its handle always points to Arcturus.

By the way, if you live as far north as Barrow, Alaska, the star Arcturus shines all night long, mimicking the midnight sun of summer.

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Halloween derived from ancient Celtic cross-quarter day