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Phases of a Red Moon

The moon is usually yellow. This is because it reflects the yellow glow from the sun. Occasionally the moon can appear orange or even red, when it is very low in the sky. This is because the moon is traveling through scattered red light on the horizon. A true red moon occurs during a lunar eclipse. An eclipse is when the moon passes behind Earth's shadow. While it is passing behind the shadow it is beyond the sun's rays. Without the yellow of the sun, it just has the red glow from Earth's atmosphere to illuminate it. A red moon goes though a series of phases.

Penumbral Moon
- The first phase of a total eclipse is the penumbral moon. This is when the moon is slightly shadowed by the earth. The penumbral phase at the beginning of an eclipse is seen from earth as a cone of light that diverges across the moon.
Partial Eclipse
- The moon moves deeper into the shadow of the earth in Phase 2 of the eclipse. This is a partial eclipse. During the partial eclipse some of the moon is visible, while some of it is hidden by Earth. Partial eclipses usually occur three or four times a year in America.
Full Eclipse
- Halfway through the phases of the red moon, the moon disappears behind the shadow of Earth. This is a full eclipse. Earth appears darker than usual during the full eclipse phase, as the moon is no longer reflecting the sun's light upon it.
Phase Reversal
- As the moon comes back into view from Earth, it repeats the previous phases in reverse. So a partial eclipse followed by a penumbral moon is visible.

Nature