A lunar eclipse occurs when the full moon passes into the shadow area of the side of earth facing away from the Sun and temporarily dims the reflecting light of the full moon. The moon initially passes through the outer partial shadow zone (penumbra) causing gradual fading of the brightness. The moon continues to move across into the deeper, darkest shadow portion of the earth (umbra) as the moon enters into a complete lunar eclipse phase. The umbra is the central dark part of the shadow that causes total solar and lunar eclipses. The penumbra is a half-shadow region that occurs when a light source is only partly covered by an object, for example, when the Moon obscures part of the Sun’s disk.