An eclipse occurs when a celestial body passes in front of the sun, blocking its light. There are two types of eclipses: lunar eclipses, where the earth casts a shadow on the moon, and solar eclipses, where the moon casts a shadow on earth. During a lunar eclipse, the earth blocks the sun's light from reaching the moon, causing it to glow red. A total lunar eclipse occurs when the moon passes completely into the earth's shadow, while a partial lunar eclipse happens when it only partially enters the shadow.

1. SSoollaarr aanndd LLuunnaarr EEcclliippsseess

2. What is an eclipse?
• An eclipse occurs any time a celestial
body passes in front of the Sun, blocking
its light.
– Examples:
1. Earth
2. The Moon

3. Celestial Bodies Line Up…
• Syzygy- When the Moon, the Earth, and
the Sun line up perfectly for an eclipse.

4. What are the types of eclipses?
• There are 2 types:
– Lunar Eclipses- When the Earth casts a shadow on
the moon, causing the moon to go dark.
• Earth comes between the Sun and the Moon and
casts a shadow on the Moon (Full Moon)
– Solar Eclipse- When the Moon casts a shadow on
the Earth, causing the sun to go dark.
• The Moon comes between the Sun and Earth and
casts a shadow on part of Earth (New Moon)

5. Parts of the shadow:
• Umbra – The dark inner portion of the shadow
cone.
– Think Direct Shadow
• Penumbral – the lighter outer portion of the
shadow.
– Think “Side” Shadow

6. Lunar Eclipse
• The Earth moves between the Sun and the Moon
– Blocks the Sun’s light
– Causes the moon to glow red.
• There are 3 types:
– Total
– Partial
– Penumbral

7. Types of Lunar Eclipses
• Total Lunar Eclipse – when the Moon passes
completely into the umbra, or total shadow, of
the Earth.
• Partial Lunar Eclipse – Occur when the Moon
does not fully move into the umbra, or total
shadow, of the Earth.
• Penumbral Lunar Eclipse – When the moon
passes only through the penumbra, or partial
shadow.
– These eclipses are barely visible.

8. Total Lunar Eclipse :
when the Moon passes completely into the umbra, or total
shadow, of the Earth:

9. So, Why is the Moon Red
during an Eclipse?
• The Earth’s atmosphere filters some sunlight
and allows it to reach the Moon’s surface
• The blue light is removed
– This light is usually scattered down to make a blue
sky over the earth in daytime
• Remaining light is red or orange
– Some of this remaining light is refracted, or bent, so
that a small part of it reaches the Moon
• Exact appearance depends on dust and clouds
in the Earth’s atmosphere
https://www.youtube.com/watch?v=a6CXLf_74AE

10. Partial Lunar Eclipse:
Occur when the Moon does not fully move into the
umbra, or total shadow, of Earth

11. Penumbral Lunar Eclipse:
When the moon passes only through the penumbra, or partial shadow.
These eclipses are barely visible.

12. 12
Solar Eclipses
• When the Moon’s shadow covers part of
the Earth
• Only happens at New Moon
• Three types:
– Annular
– Partial
– Total

13. Types of Solar Eclipses
• Total Solar Eclipse – can only occur if you are at the
exact spot within the moon’s umbra (which isn’t very
big).
• Partial Solar Eclipse – Visible is you are in the
penumbra of the shadow.
– Only some of the moon will be shadowed.
• Annular Eclipse – occurs when the moon is farthest
from the Earth in its orbit.
– Moon look smaller, so during the eclipse you see an outer
ring of light from the Sun.

14. 14
Total Solar Eclipse
• Observers in the “umbra” shadow  see a total eclipse
– (safe to view the Sun); can see the corona (Outside layer of sun)
• Those in “penumbra”  see a partial eclipse
– not safe to look directly at Sun
• Only lasts a few minutes
• Path of Totality about 10,000 miles long, only 100 miles wide

15. Total Solar Eclipse:
can only occur if you are at the exact spot within the
moon’s umbra (which isn’t very big).

16. 16
Photo of a Total Eclipse
https://www.youtube.com/watch?v=xx3EwETgN38

17. Partial Solar Eclipse:
Visible if you are in the penumbra of the shadow.
-Only some of the moon will be shadowed.

18. 18
Annular Solar Eclipse
• When the Moon is too far to completely cover the Sun—the umbra doesn’t
reach the Earth
• Sun appears as a donut around the Moon

19. Annular Solar Eclipse:
•Occurs when the moon is farthest from the Earth in its orbit.
•Moon look smaller, so during the eclipse you see an outer ring of light from the Sun.

20. 20
Photos of an Annular Eclipse
http://sunearthday.nasa.gov/2006/multimedia/gal_010.php; photos taken by Fred Espenak

21. How often do Eclipses Happen?
• That depends!!
– Lunar Eclipses happen more often than Solar Eclipses.
• Why?
– Well everyone who is experiencing nighttime during a
lunar eclipse can see it.
• But you have to be at the exact spot on Earth to
see a Solar Eclipse.
• The spot on Earth is so small, that the same place
only sees a Solar Eclipse every 350 years!!

22. When will the next Eclipse happen?
Date Type of
Eclipse
Where What will the Eclipse Look
Like?
March 20,
2015
Total Solar
Eclipse
-Europe
-North/East Asia
-North/West Africa
-West in North America
-Atlantic
-Arctic
April 4,
2015
Partial Lunar
Eclipse
-Much of Asia
-Australia
-Much of North America
-Much of South America
-Pacific, Atlantic, Indian Ocean
-Arctic
-Antarctica
September
13, 2015
Partial Solar
Eclipse
-South in Africa
-Atlantic
- Indian Ocean
- Antarctica
September
28, 2014
Total Lunar
Eclipse
-Europe
-South/East Asia
-Africa
-Much of North America
-Much of South America
-Pacific, Atlantic, Indian Ocean
-Arctic
-Antarctica