Eclipses
Solar Eclipse
• Occurs when the Moon is positioned
between the Sun and Earth and all
are in complete alignment
• Occurs during a NEW Moon
• The Moon’s shadow falls on a portion
of the Earth
The Geometry of a Solar Eclipse
Another View of Solar Eclipse Geometry
Total Solar Eclipse
• Occurs when the Moon's umbral shadow
sweeps across Earth's surface.
• The track is typically 10,000 miles long but no
more than 167 miles wide. It covers less than
1% of Earth's entire surface area.
• In order to see the Sun become completely
eclipsed by the Moon, you must be somewhere
inside the umbra.
Total Solar Eclipse
Partial Solar Eclipse
• Partial solar eclipses are visible from
within the penumbra.
• Remember, the penumbral part of the
shadow is larger than the umbral part
of the shadow cone
Partial Solar Eclipse
Annular Eclipse
• Occurs when the Moon is too far
from Earth to cover the Sun
completely
• Outer edge of the Sun is seen as a
ring
Annular Eclipse:
Beginning, During and Ending
2012- 2013 Eclipses
Date
Eclipse
Type
May 20, 2012
Solar
Annular
June 4, 2012
Lunar
Partial
November 13, 2012
Solar
Total
November 28, 2012
Lunar
Penumbral
April 25, 2013
Lunar
Partial
May 10, 2013
Solar
Annular
May 25, 2013
Lunar
Penumbral
October 18, 2013
Lunar
Penumbral
November 3, 2013
Solar
Hybrid (?)
Lunar Eclipse:
• Occurs when the Earth is positioned
between the Sun and the Moon and all
three bodies are in complete alignment
• Occurs during the FULL Moon phase
• The Earth’s shadow falls on the Moon
• Lunar eclipses will be seen by everyone
experiencing night
The Geometry of a Lunar Eclipse
3 Types of Lunar Eclipses
(But we’re only discussing Total and Partial Eclipses)
West
East
Total Lunar Eclipse
• Occurs when the entire Moon falls
within the Earth’s umbra
• The Moon appears reddish
The Geometry of a Total Lunar Eclipse
Total Lunar Eclipse
Partial Lunar Eclipse
• Occurs when part of the Moon falls
within Earth’s umbra
The Geometry of a Partial Lunar Eclipse
Only a portion of the Moon falls in Earth’s umbra.
Partial Lunar Eclipse
Penumbral Lunar Eclipse
Comparing Solar and Lunar Eclipses
Differences
Solar
Lunar
Involves the Sun, Moon and Earth
Involves the Sun, Earth and Moon
Requires a New Moon
Requires a Full Moon
Occurs during the day
Occurs at night
Seen over a narrow geographic area
Seen by everyone experiencing night
Can NEVER, EVER be looked at directly
Safe to look at
Similarities
Both occur at 5 month, 3 week intervals
Can only occur when SEM or SME are directly lined up