Solar and Lunar Eclipses

Lunar Eclipses

A lunar eclipse occurs when the Earth passes between the Sun and Moon, casting its shadow on the Moon. Lunar eclipses can only occur at full moon.

• Total Lunar Eclipse - The Moon passes through Earth's umbra (dark inner shadow). The Moon often appears reddish due to sunlight refracted through Earth's atmosphere.
• Partial Lunar Eclipse - Only part of the Moon passes through the umbra.
• Penumbral Lunar Eclipse - The Moon passes only through Earth's penumbra (outer, lighter shadow). The darkening is subtle.

Solar Eclipses

A solar eclipse occurs when the Moon passes between Earth and Sun, blocking the Sun. Solar eclipses can only occur at new moon.

• Total Solar Eclipse - The Moon completely covers the Sun. The Sun's corona becomes visible. Only visible along a narrow path.
• Partial Solar Eclipse - The Moon only partly covers the Sun.
• Annular Solar Eclipse - The Moon is near apogee (farthest from Earth) and appears smaller, leaving a ring of sunlight visible.

Why Don't Eclipses Happen Every Month?

The Moon's orbit is tilted about 5° to Earth's orbital plane. Eclipses only occur when the Moon is near one of its orbital nodes (where it crosses the ecliptic) at the same time as new or full moon.