Eclipses

Lunar and Solar Eclipses

Sun and Moon have almost the same angular diameters

• Each subtend an angle ~ ½ degree

• Sun is 400 times larger than the Moon and 400 times further away

Solar and Lunar Eclipses

• Everyone on Dark side of Earth sees a Lunar Eclipse, only a few will see a solar eclipse – shadow sizes!

Slight change in lunar size due to its elliptical orbit around the Earth

• Causes annular and total solar eclipses

Total Solar Eclipse

• Moon’s shadow barely reaches the Earth

Lunar Eclipse

• Earth Shadow easily covers the Moon

Total Solar Eclipse

• Eclipse Path and Partial Eclipse

Solar Eclipses

• Corona, comets and diamond ring effect

Annular Eclipse

• Moon near apogee (too far away)

Lunar Eclipse is often Reddish

• Due to refraction of Earth’s atmosphere

Red Color and Earth’s Shadow

• Red color near edges of shadow

Eclipses occur ~ every 6 months

• Line of nodes must point toward the Sun

• The alignment is not exact (eclipse limits)