Watch: What a total lunar eclipse is and how it is formed

The lunar eclipse occurs on a full Moon day when the Earth comes in between the Sun and the Moon and when all the three objects are aligned. The Moon darkens and turns red as a result of sunlight refracting through the Earth’s atmosphere. When the Sun, Earth, and Moon come together in a straight line, it results in a total lunar eclipse. When the three bodies are aligned in a way that the Moon is partly covered by the Earth's umbra, a partial lunar eclipse takes place. And, if only the outer part of Earth's shadow covers the Moon, a penumbral lunar eclipse takes place. A total lunar eclipse is very rare and only occurs when the Moon is entirely covered by the Earth’s shadow.