Illumination of Earth by Sun at the southern solstice.
This season’s Solstice (Winter in the Northern hemisphere, Summer in the Southern), occurs at 23:38pm UTC on December 21, 2008. That’s 5:38 PM tomorrow evening where I am, in the Eastern Time zone.
The name is derived from the Latin sol (sun) and sistere (to stand still), because at the solstices, the Sun stands still in declination; that is, its apparent movement north or south comes to a standstill.
– Solstice, Wikipedia
This year’s Winter Solstice is remarkable for an unusual astronomical coincidence: The lunar eclipse occurring later tonight, early tomorrow morning. I’ve seen a range of reports on the last time this occurred, from 372 to 645 years. According to Wikipedia, the last time this occurred was in 1638. Whatever, it’s in centuries, so rare enough for my lifetime.
In the New York area, the eclipse will officially begin on December 21 at 12:29 am as the Moon begins to enter Earth’s outer, or penumbral, shadow. But even in clear weather sky watchers will not notice any changes in the Moon’s appearance until about 1:15 am, when a slight “smudge” or shading begins to become evident on the upper left portion of the Moon’s disk. The first definitive change in the Moon’s appearance will come on the Moon’s upper left edge. At 1:33 am the partial phase of the eclipse will begin as the Earth’s dark shadow–called the umbra–starts to slowly creep over the face of the full Moon. At that moment the Moon will be roughly two-thirds of the way up in the sky as measured from the southwest horizon to the point directly overhead.
At 2:41 am the eclipse will reach totality, but sunlight bent by our atmosphere around the curvature of the Earth should produce a coppery glow on the Moon. At this time, the Moon, if viewed with binoculars or a small telescope, will present the illusion of seemingly glowing from within by its own light.
At 3:17 am the Sun, Earth and Moon will be almost exactly in line and, assuming clear skies, the light of the Moon will appear at its dimmest. Totality ends at 3:53 am, and the Moon will completely emerge from the umbra and return to its full brilliance at 5:01 am. By then the Moon will have descended to a point about one-quarter up from above the west-northwest horizon.
– December 20-21: The Night of the Red Moon, Hayden Planetarium, American Museum of Natural History
Related Posts
2009: Standing Still, Looking Ahead
2008: Stand Still / Dona Nobis Pacem
2007: Solstice: The Sun Stands Still
Links
Wikipedia: Solstice
Wikipedia: December 2010 Lunar Eclipse
December 20-21: The Night of the Red Moon, Hayden Planetarium, American Museum of Natural History
Lunar eclipse Monday night, Bad Astronomer