Monday, December 20, 2010

The Solstice Eclipse

Despite the gloomy weather, Bay Area skywatchers and mere curiosity seekers like myself are tracking tonight's total lunar eclipse. It is a very rare event because it falls on the same day as the northern winter solstice -- the moment at which the Earth's north axis is tilted farthest from the sun, giving us our shortest day and longest night of the year, and heralding the first day of winter. According to NASA Science News, there's only been one other lunar eclipse on the northern winter solstice in the last 2,000 years . . . and that one was back in 1638.

According to information from Oakland's Chabot Space & Science Center, the eclipse begins -- or began, because it's underway now -- when the Earth's shadow starts to slide across the full moon at 9:30 p.m. Monday night, December 20 (tonight). Complete coverage -- known to astronomers as "totality" -- lasts from 11:40 p.m. until 12:53 a.m. on Tuesday, December 21, and the eclipse should be over by 2:00 a.m.

The photo above was taken at 10:40 p.m. from our backyard. The splendid full moon of the solstice can been seen through a thin veiling of fog. It looks like the Christmas star, but don't try to follow it!

I took this follow-up photo at 11:50 p.m., ten minutes past "totality." What I saw -- or thought I saw -- and tried to get a picture of was the last tiny fingernail clipping of light disappearing behind a thicker layer of fog. I don't know why it was still visible at that point in the process. When I enhanced the photo there was indeed a small pale smudge in the center, but I couldn't get the enhanced photo to upload. There are far better photos and videos of the whole event all over the internet; nonetheless, it's nice to keep a personal vantage point on the cosmos from one's own backyard.

Besides tracking the eclipse, I also marked the solstice by hanging the first section of this marvelous calendar which provides a beautiful wall poster for each quartile of the natural year: winter solstice to spring equinox, spring equinox to summer solstice, summer solstice to fall equinox, and fall equinox to winter solstice.

The reddish circle on the left edge is the solstice lunar eclipse, which marks the beginning of another cycle of light in our journey round the sun.

Note about the calendar: The link goes to the 2010 calendar at Amazon but I know the 2011 version is available. I bought mine at Whole Foods.

Note about the time stamp: Blogger has an interesting habit of marking the time the first draft of a post is saved. I started this post earlier in the evening and saved the draft, worked on it some more later and didn't actually publish until a few days afterwards. But the date and time stamps show the time of the first draft.

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