When the moon is at either position C or G, a person directly below the Moon would observe that half of the Moon’s facing surface is lit by the Sun. Position A shows the new moon phase (none of the facing surface is lit). Position E shows the full Moon phase (unless a lunar eclipse is occurring). Positions B and H show crescent Moon phases (most of the facing surface is unlit). Positions D and F show autumn moon phases (most of the facing surface is lit).