You may have noticed that it has been a little chilly lately. Winter has arrived. The first day of winter in the northerm hemisphere, the winter solstice, is Tuesday December 21, 2010. This solstice also marks the first day of summer in the southern hemisphere.
The instant of the winter solstice is 6:38 PM Eastern standard time. At this time, the Sun will be overhead on the Tropic of Capricorn at a latitude of 23.5 degrees south. The winter solstice also marks the time when the Sun appears furthest south as seen from Earth.
In an unusual coincidence the 2010 winter solstice is on the same day as a total lunar eclipse. This eclipse of the Moon will be visible from North America, the Pacific, and eastern Asia. The eclipse will occur before dawn on the morning of December 21. In more western locations it will start on the night of Monday December 20.
As Earth continues its orbit around the Sun, the Sun will appear to move northward in the sky. This apparent north-south motion of the Sun in the sky causes the seasons. Contrary to popular belief, the seasons are not in any way caused by the changing distance between Earth and the Sun. In fact Earth is at its closest point to the Sun on January 3, 2011.
Break out your warm clothes for the first day of winter and enjoy a total lunar eclipse on the winter solstice.
http://www.examiner.com/astronomy-i...day-of-winter-2010-offers-total-lunar-eclipse
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The 12 stages of Monday's total lunar eclipse
A guide to prepare you for this rare and beautiful event
The various stages, fully described:
1) Moon enters penumbra (12:29 a.m. EST/9:29 p.m. PST) The shadow cone of the earth has two parts: a dark, inner umbra, surrounded by a lighter penumbra. The penumbra is the pale outer portion of the Earth's shadow. Although the eclipse begins officially at this moment, this is in essence an academic event. You won't see anything unusual happening to the moon - at least not just yet.
The Earth's penumbral shadow is so faint that it remains invisible until the moon is deeply immersed in it. We must wait until the penumbra has reached roughly 70 percent across the moon's disk. For about the next 45 minutes the full moon will continue to appear to shine normally although with each passing minute it is progressing ever deeper into the Earth's outer shadow.
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2) Penumbral shadow begins to appear (1:13 a.m. EST/10:13 p.m. PST) Now the moon has progressed far enough into the penumbra so that it should be evident on its disk. Start looking for a very subtle light shading to appear on the moon's upper left portion. This will become increasingly more and more evident as the minutes pass; the shading will appear to spread and deepen. Just before the moon begins to enter the Earth's dark umbral shadow the penumbra should appear as an obvious smudge or tarnish on the moon's left portion.
3) Moon enters umbra (1:33 a.m. EST/10:33 p.m. PST) The moon now begins to cross into the Earth's dark central shadow, called the umbra. A small dark scallop begins to appear on the moon's upper left-hand (northeastern) limb. The partial phases of the eclipse begin; the pace quickens and the change is dramatic. The umbra is much darker than the penumbra and fairly sharp-edged.
As the minutes pass the dark shadow appears to slowly creep across the moon's face. At first the moon's limb may seem to vanish completely inside of the umbra, but much later, as it moves in deeper you'll probably notice it glowing dimly orange, red or brown. Notice also that the edge of the Earth's shadow projected on the moon is curved. Here is visible evidence that the Earth is a sphere, as deduced by Aristotle from Iunar eclipses he observed in the 4th century B.C.
Almost as if a dimmer switch was slowly being turned down, the surrounding landscape and deep shadows of a brilliant moonlit night begin to fade away.
4) 75 percent coverage (2:23 a.m. EST/11:23 p.m. EST) With three-quarters of the moon's disk now eclipsed, that part of it that is immersed in shadow should begin to very faintly light up similar to a piece of iron heated to the point where it just begins to glow. It now becomes obvious that the umbral shadow is not complete darkness. Using binoculars or a telescope, its outer part is usually light enough to reveal lunar seas and craters, but the central part is much darker, and sometimes no surface features are recognizable.
Colors in the umbra vary greatly from one eclipse to the next. Reds and grays usually predominate, but sometimes browns, blues and other tints are encountered.
5) Less than five minutes to totality (2:37 a.m. EST/11:37 p.m. PST) Several minutes before (and after) totality, the contrast between the remaining pale-yellow sliver and the ruddy-brown coloration spread over the rest of the moon's disk may produce a beautiful phenomenon known to some as the "Japanese lantern effect. "
6) Total eclipse begins (2:41 a.m. EST/11:41 p.m. PST) When the last of the moon enters the umbra, the total eclipse begins. How the moon will appear during totality is not known. Some eclipses are such a dark gray-black that the moon nearly vanishes from view. During other eclipses it can glow a bright orange.
The reason the moon can be seen at all when totally eclipsed is that sunlight is scattered and refracted around the edge of the Earth by our atmosphere. To an astronaut standing on the moon during totality, the sun would be hidden behind a dark Earth outlined by a brilliant red ring consisting of all the world's sunrises and sunsets.
The brightness of this ring around the earth depends on global weather conditions and the amount of dust suspended in the air. A clear atmosphere on Earth means a bright lunar eclipse. If a major volcanic eruption has injected particles into the stratosphere, the eclipse is very dark.
Because of the recent eruptions of the Eyjafjallajull volcano in Iceland last spring and the Merapi volcano in Indonesia in October, one and possibly two clouds of ash and dust might be currently floating high above the Earth. As a result, the moon may appear darker than usual during this eclipse; during totality, parts of the moon might even become black and invisible.
More
Merry Solstice All
The instant of the winter solstice is 6:38 PM Eastern standard time. At this time, the Sun will be overhead on the Tropic of Capricorn at a latitude of 23.5 degrees south. The winter solstice also marks the time when the Sun appears furthest south as seen from Earth.
In an unusual coincidence the 2010 winter solstice is on the same day as a total lunar eclipse. This eclipse of the Moon will be visible from North America, the Pacific, and eastern Asia. The eclipse will occur before dawn on the morning of December 21. In more western locations it will start on the night of Monday December 20.
As Earth continues its orbit around the Sun, the Sun will appear to move northward in the sky. This apparent north-south motion of the Sun in the sky causes the seasons. Contrary to popular belief, the seasons are not in any way caused by the changing distance between Earth and the Sun. In fact Earth is at its closest point to the Sun on January 3, 2011.
Break out your warm clothes for the first day of winter and enjoy a total lunar eclipse on the winter solstice.
http://www.examiner.com/astronomy-i...day-of-winter-2010-offers-total-lunar-eclipse
-----------------------------------
The 12 stages of Monday's total lunar eclipse
A guide to prepare you for this rare and beautiful event
The various stages, fully described:
1) Moon enters penumbra (12:29 a.m. EST/9:29 p.m. PST) The shadow cone of the earth has two parts: a dark, inner umbra, surrounded by a lighter penumbra. The penumbra is the pale outer portion of the Earth's shadow. Although the eclipse begins officially at this moment, this is in essence an academic event. You won't see anything unusual happening to the moon - at least not just yet.
The Earth's penumbral shadow is so faint that it remains invisible until the moon is deeply immersed in it. We must wait until the penumbra has reached roughly 70 percent across the moon's disk. For about the next 45 minutes the full moon will continue to appear to shine normally although with each passing minute it is progressing ever deeper into the Earth's outer shadow.
advertisement | ad info
Advertisement | ad info
Advertisement | ad info
2) Penumbral shadow begins to appear (1:13 a.m. EST/10:13 p.m. PST) Now the moon has progressed far enough into the penumbra so that it should be evident on its disk. Start looking for a very subtle light shading to appear on the moon's upper left portion. This will become increasingly more and more evident as the minutes pass; the shading will appear to spread and deepen. Just before the moon begins to enter the Earth's dark umbral shadow the penumbra should appear as an obvious smudge or tarnish on the moon's left portion.
3) Moon enters umbra (1:33 a.m. EST/10:33 p.m. PST) The moon now begins to cross into the Earth's dark central shadow, called the umbra. A small dark scallop begins to appear on the moon's upper left-hand (northeastern) limb. The partial phases of the eclipse begin; the pace quickens and the change is dramatic. The umbra is much darker than the penumbra and fairly sharp-edged.
As the minutes pass the dark shadow appears to slowly creep across the moon's face. At first the moon's limb may seem to vanish completely inside of the umbra, but much later, as it moves in deeper you'll probably notice it glowing dimly orange, red or brown. Notice also that the edge of the Earth's shadow projected on the moon is curved. Here is visible evidence that the Earth is a sphere, as deduced by Aristotle from Iunar eclipses he observed in the 4th century B.C.
Almost as if a dimmer switch was slowly being turned down, the surrounding landscape and deep shadows of a brilliant moonlit night begin to fade away.
4) 75 percent coverage (2:23 a.m. EST/11:23 p.m. EST) With three-quarters of the moon's disk now eclipsed, that part of it that is immersed in shadow should begin to very faintly light up similar to a piece of iron heated to the point where it just begins to glow. It now becomes obvious that the umbral shadow is not complete darkness. Using binoculars or a telescope, its outer part is usually light enough to reveal lunar seas and craters, but the central part is much darker, and sometimes no surface features are recognizable.
Colors in the umbra vary greatly from one eclipse to the next. Reds and grays usually predominate, but sometimes browns, blues and other tints are encountered.
5) Less than five minutes to totality (2:37 a.m. EST/11:37 p.m. PST) Several minutes before (and after) totality, the contrast between the remaining pale-yellow sliver and the ruddy-brown coloration spread over the rest of the moon's disk may produce a beautiful phenomenon known to some as the "Japanese lantern effect. "
6) Total eclipse begins (2:41 a.m. EST/11:41 p.m. PST) When the last of the moon enters the umbra, the total eclipse begins. How the moon will appear during totality is not known. Some eclipses are such a dark gray-black that the moon nearly vanishes from view. During other eclipses it can glow a bright orange.
The reason the moon can be seen at all when totally eclipsed is that sunlight is scattered and refracted around the edge of the Earth by our atmosphere. To an astronaut standing on the moon during totality, the sun would be hidden behind a dark Earth outlined by a brilliant red ring consisting of all the world's sunrises and sunsets.
The brightness of this ring around the earth depends on global weather conditions and the amount of dust suspended in the air. A clear atmosphere on Earth means a bright lunar eclipse. If a major volcanic eruption has injected particles into the stratosphere, the eclipse is very dark.
Because of the recent eruptions of the Eyjafjallajull volcano in Iceland last spring and the Merapi volcano in Indonesia in October, one and possibly two clouds of ash and dust might be currently floating high above the Earth. As a result, the moon may appear darker than usual during this eclipse; during totality, parts of the moon might even become black and invisible.
More
Merry Solstice All
