A lunar eclipse is an astronomical event that occurs when the Moon moves into the Earths shadow, causing the Moon to be darkened. This alignment occurs during an eclipse season, approximately every six months, during the full moon phase, when the Sun, Earth, and Moon align so that the Moon passes into Earths shadow. There are three types of lunar eclipses depending on how the Sun, Earth, and Moon are aligned at the time of the event: total lunar eclipse, partial lunar eclipse, and penumbral lunar eclipse. During a total lunar eclipse, the entire Moon falls within the darkest part of Earths shadow, called the umbra, and turns a reddish hue due to the sunlight passing through Earths atmosphere. Lunar eclipses are sometimes called "Blood Moons" because of this phenomenon. A partial lunar eclipse occurs when only a portion of the Moon passes through Earths umbra, while a penumbral lunar eclipse occurs when the Moon passes through Earths penumbra, the faint outer part of its shadow. Lunar eclipses can be observed with the naked eye, and binoculars or a telescope can enhance the view and the red color.