1. Eclipses

2. Eclipses
When the Sun or Moon is blocked to an observer on Earth over a short period of time (minutes to hours) an eclipse has occurred.
If the Sun is blocked it is a solar eclipse.
If the Moon is blocked it is lunar eclipse.
Eclipses are named for what you can not see.

3. Solar Eclipse When the Moon’s shadow covers part of the Earth
Only happens at New Moon
Order: Sun, Moon, Earth

4. Total Solar Eclipse

5. Why doesn’t everyone see a Solar Eclipse?
When the Moon passes directly between the Earth and the Sun, the Moon casts a shadow on the Earth. Where the shadow falls, observers will see an eclipse of the Sun, a solar eclipse.
If the entire Sun is covered we see a total eclipse; of only part if the surface is blocked we see a partial eclipse.

6. The blue line shows the path of the next total solar eclipse.
It’ll occur on August 21, 2017

7. Lunar Eclipse
When the Moon is in the full moon position, the light from the Sun may be blocked by the Earth which casts a shadow.
As the Moon travels into the shadow it is gradually covered.
Order: Sun, Earth, Moon

8. Shouldn’t there be a lunar eclipse every time we have a full moon?
The Moon orbits Earth on a plane, but that plane is tilted 5o compared to the path the Earth and Sun take. This means that when the moon is in the full position it may be above or below the shadow of the Earth and no eclipse will occur.
Earth’s path
Moon’s Path