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24 Cards in this Set
- Front
- Back
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North Celestial Pole |
The point directly over Earth's North Pole |
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South Celestial Pole |
The point directly over Earth's South Pole |
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Celestial Equator |
A projection of Earth's equator into space, makes a complete circle around the celestial sphere |
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Local Sky |
The sky as seen from wherever you are standing |
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Direction/Azimuth |
Direction around the horizon from due North, measured clockwise in degrees |
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Altitude |
The angular distance between the horizon and an object in the sky |
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Eclipses |
Shadows created when the Sun, Moon, and Earth fall in a straight line |
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Lunar Eclipse |
Occurs when Earth lies directly between the Sun and the Moon, so that Earth's shadow falls on the Moon |
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Solar Eclipse |
Occurs when the Moon lies directly between the Sun and Earth, so that the Moon's shadow falls on Earth |
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Nodes |
The two points in the Moon's orbit where it crosses the ecliptic plane |
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Umbra |
The dark central region of a shadow |
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Penumbra |
The lighter, outlying regions of a shadow |
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Total Lunar Eclipse |
A lunar eclipse in which the Moon becomes fully covered by Earth's umbral shadow |
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Partial Lunar Eclipse |
A lunar eclipse during which the Moon becomes only partially covered by Earth's umbral shadow |
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Penumbral Lunar Eclipse |
A lunar eclipse during which the Moon passes only within Earth's penumbral shadow and does not fall within the umbra |
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Totality |
The portion of a total lunar eclipse during which the Moon is fully within Earth's umbral shadow or a total solar eclipse during the Sun's disk is fully blocked by the Moon |
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Total Solar Eclipse |
A solar eclipse during which the Sun becomes fully blocked by the disk of the Moon |
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Total Solar Eclipse |
A solar eclipse during which the Sun becomes fully blocked by the disk of the Moon |
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Partial Solar Eclipse |
A solar eclipse during which the Sun becomes partially blocked by the disk of the Moon |
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Annular Eclipse |
A solar eclipse during which the Moon is directly in front of the Sun but it's angular size in not large enough to fully block the Sun, a ring of sunlight is visible around the Moon's disk |
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Saros Cycle |
The period over which the basic pattern of eclipse repeats, which is about 18 years and 11 1/3 days |
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Solar day |
The time between successive passages of the sun across the meridian which is a line drawn directly overhead from the South Pole to North Pole |
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Sidereal Day |
The time between successive passages of a star across the meridian |
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Features of the Moon's Orbit |
1) radius of Moon's orbit is 380,000 km 2) Moon's diameter is 3,476 km 3) Moon orbits the Earth once every 27.3 days 4) orbit of the moon is tilted 5 degree and precesses once every 18.5 years |
