Eclipses Key Terms

Penumbral Lunar Eclipse

A lunar eclipse during which the Moon passes only within Earth's penumbral shadow and does not fall within the umbra.

Annular Eclipse

A type of solar eclipse in which the Moon is too far from Earth to cover the Sun completely, so the outer edge of the Sun is seen as a ring.

Partial Lunar Eclipse

An eclipse in which part of the full moon's illuminated disk becomes temporary darkened by Earth's shadow; occurs when the Moon moves partially into the umbra of Earth's shadow.

Partial Solar Eclipse

An eclipse in which the new moon temporarily blocks part of the Sun's disk; occurs when the new moon, Earth, and the Sun are not completely aligned and the umbra of the Moon's shadow falls into space and viewers on Earth are located in the penumbra of the Moon's shadow.

Total Lunar Eclipse

Eclipse in which the entire disk of the full moon is covered by Earth's umbra.

Total Solar Eclipse

Eclipse visible on Earth from inside the Moon's umbra; occurs when the Sun's entire disk- except for the corona is blocked by the new moon.

Full Moon

The Moon phase during which a lunar eclipse can occur.

New Moon

The Moon phase during which a solar eclipse can occur.

Sun-Earth-Moon

The alignment for a lunar eclipse to occur.

Sun-Moon-Earth

The alignment for a solar eclipse to occur.

Eclipse

The complete or partial blocking of light from the Sun and Moon that occurs when the Moon passes between the Sun and Earth and casts a shadow on Earth, or when the Moon enters the shadow of Earth.

Umbra

The inner, darker part of a shadow.

Penumbra

The light, outer part of a shadow cone.