Lunar Eclipse
Lunar eclipse
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[pic]
The June 2011 total eclipse
A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the Sun, Earth, and Moon are aligned (in "syzygy") exactly, or very closely so, with the Earth in the middle. Hence, a lunar eclipse can only occur the night of a full moon. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes. Unlike a solar eclipse, which can only be viewed from a certain relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of the Earth. A lunar eclipse lasts for a few hours, whereas a total solar eclipse lasts for only a few minutes at any given place, due to the smaller size of the moon's shadow. Also unlike solar eclipses, lunar eclipses are safe to view without any eye protection or special precautions, as they are no brighter (indeed dimmer) than the full moon itself.
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Types of lunar eclipse
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[pic]
Schematic diagram of the shadow cast by the Earth. Within the central umbra shadow, the Moon is totally shielded from direct illumination by the Sun. In contrast, within the penumbrashadow, only a portion of sunlight is blocked.
[pic]
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As seen by an observer on Earth on the imaginary celestial sphere, the Moon crosses the ecliptic every orbit at positions called nodes twice every month. When the full moon occurs in the same position at the node, a lunar eclipse can occur. These two nodes allow two to five eclipses per year, parted by approximately six months. (Note: Not drawn to scale. The Sun is much larger and farther away than the Moon.)
[pic]
[pic]
A total penumbral lunar eclipse dims the moon in direct proportion to the area of the sun’s disk blocked by the earth. This comparison shows the southern shadow penumbral lunar eclipse ofJanuary 1999 (left) to the same moon outside of the shadow (right) demonstrates this subtle dimming.
The shadow of
[pic]
[pic]
The June 2011 total eclipse
A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the Sun, Earth, and Moon are aligned (in "syzygy") exactly, or very closely so, with the Earth in the middle. Hence, a lunar eclipse can only occur the night of a full moon. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes. Unlike a solar eclipse, which can only be viewed from a certain relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of the Earth. A lunar eclipse lasts for a few hours, whereas a total solar eclipse lasts for only a few minutes at any given place, due to the smaller size of the moon's shadow. Also unlike solar eclipses, lunar eclipses are safe to view without any eye protection or special precautions, as they are no brighter (indeed dimmer) than the full moon itself.
| |
Types of lunar eclipse
[pic]
[pic]
Schematic diagram of the shadow cast by the Earth. Within the central umbra shadow, the Moon is totally shielded from direct illumination by the Sun. In contrast, within the penumbrashadow, only a portion of sunlight is blocked.
[pic]
[pic]
As seen by an observer on Earth on the imaginary celestial sphere, the Moon crosses the ecliptic every orbit at positions called nodes twice every month. When the full moon occurs in the same position at the node, a lunar eclipse can occur. These two nodes allow two to five eclipses per year, parted by approximately six months. (Note: Not drawn to scale. The Sun is much larger and farther away than the Moon.)
[pic]
[pic]
A total penumbral lunar eclipse dims the moon in direct proportion to the area of the sun’s disk blocked by the earth. This comparison shows the southern shadow penumbral lunar eclipse ofJanuary 1999 (left) to the same moon outside of the shadow (right) demonstrates this subtle dimming.
The shadow of
References: • [pic] December 21, 2010 Lunar Eclipse