When the moon moves between the sun and the earth, the moon casts a shadow that touches the surface of the earth, either completely or partly, is called solar eclipse. This can only happen at new moon. The given figure illustrated the solar eclipse. The shadow cast by the Moon can be divided into the completely shadowed umbra(U) and partially shadowed penumbra(P). when the moon moves through the shadow caste by the earth is called lunar eclipse. The lunar eclipse only happens at full moon.

Total eclipses occur where the light source is totally blocked off by the eclipsing body. Partial eclipses occur at places where only part of the luminary is covered (solar eclipses), or when only part of a body is eclipsed by the shadow (lunar eclipses).