What is a lunar eclipse? A lunar eclipse occurs when the Moon lines up precisely behind the Earth so that the Earth blocks the Sun’s rays and the Earths shadow falls upon the Moon. This relatively rare occurrence only happens when the Moon, Earth and Sun are exactly or very closely aligned, with the Earth in the middle. The shadow cast can partially or totally cover the Moon, creating partial eclipses and total eclipses for our viewing pleasure. The type and length of a lunar eclipse depends upon the Moon’s location relative to its orbital nodes. A lunar eclipse lasts for a few hours and can be viewed from anyone on the night side of the Earth. Because lunar eclipses are no brighter than the full moon itself, they are safe to observe without any eye protection or special precautions.