Eclipse mechanics, illustration. At left is the Moon (red) as seen during a lunar eclipse. At right are the Sun and Moon, as seen during a total solar eclipse, with the Sun's corona visible around the Moon. The main diagram shows the relative positions of the Earth and Moon during these events. The Sun is off screen to the right, shown by the yellow arrow. During a total solar eclipse, the Moon passes in front of the Sun, and the Moon's shadow (umbra) is cast on the Earth at the point of totality. During a lunar eclipse, the Earth passes between the Moon and the Sun, and the Earth's shadow (umbra) is cast on the Moon. The red colour is due to the effect of sunlight passing through the Earth's atmosphere to reach the Moon.