Thursday, September 23, 2010

Autum begins beautifully

"For the first time in almost 20 years, northern autumn is beginning on the night of a full moon. The coincidence sets the stage for a 'Super Harvest Moon' and a must-see sky show to mark the change of seasons."

Today is the equinox (get the rake ready) but it is also the night of a truly beautiful full moon. If you can, try to get outside and see it, for not only is this a rare occurance, it also is a great night to spy Jupiter in the sky.

The equinox itself is when the Earth reaches the midpoint on its way from one of the "points" of the elipse to the other. It marks a calendar day where there is an equal number of sunlit hours as there are moonlit hours. This year, it has matched the lunar equinox (the full moon) giving a very bright night (your milage may vary due to clouds). The exact moment of the Earth's equinox was at 11:09 PM, EDT; the exact moment of the lunar equinox (when the moon is at its fullest) will be at 4:47 AM, EDT. The best part of this spectacle, thus, is happening right now, as I write this, during the 6 hours in between (it should also be visible tomorrow, but no guarantees).

"That's all very nice, but why does it even matter?" Well, it's the first full moon of autumn, meaning that it's the harvest moon, which rarely falls on the equinox itself. Dr. Philips probably explains it best:
"The Harvest Moon gets its name from agriculture. In the days before electric lights, farmers depended on bright moonlight to extend the workday beyond sunset. It was the only way they could gather their ripening crops in time for market. The full moon closest to the autumnal equinox became 'the Harvest Moon,' and it was always a welcome sight."
But the beauty doesn't end there. As I mentioned, Jupiter will be visible with the naked eye, and easily locatable. At midnight (15 minutes ago in my time zone) it was the only thing to the right of the moon. Big and bright. Now, how likely is it that Jupiter is at the point of its orbit where it's perfectly aligned with the Earth like that? Relly, get up from your computer and take a look at it.

Many thanks to Angela Atadia for her version of Dr. Philips's article.

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