A lunar eclipse occurs when the Moon passes directly behind the Earth into its umbra (shadow). This can occur only when the sun, Earth and moon are aligned (in syzygy) exactly, or very closely so, with the Earth in the middle. Hence, a lunar eclipse can occur only the night of a full moon. The type and length of an eclipse depend upon the Moon's location relative to its orbital nodes. A total lunar eclipse has the direct sunlight completely blocked by the earth's shadow. The only light seen is refracted through the earth's shadow.
https://en.wikipedia.org/wiki/Lunar_eclipse
An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer. An eclipse is a type of syzygy. The term eclipse is most often used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's surface, or a lunar eclipse, when the Moon moves into the Earth's shadow.
https://en.wikipedia.org/wiki/Eclipse
A solar eclipse is an eclipse of the Sun. It happens when the Moon passes between the Earth and the Sun. This is only possible when the Moon is in the New Moon phase. For more information, see Solar Eclipses for Beginners.
http://mreclipse.com/Special/LEprimer.html
A partial lunar eclipse occurs when only a portion of the moon enters the umbra. When the moon travels completely into the Earth's umbra, one observes a total lunar eclipse. The moon's speed through the shadow is about one kilometer per second (2,300 mph), and totality may last up to nearly 107 minutes.
https://en.wikipedia.org/wiki/Lunar_eclipse
It happens because the Moon is directly opposite the Sun in the sky when the Moon is Full. Full Moon also has special significance with regard to eclipses. Geometry of the Sun, Earth and Moon During an Eclipse of the Moon. Earth's two shadows are the penumbra and the umbra.
http://mreclipse.com/Special/LEprimer.html
Solar Eclipses | Lunar Eclipses. 21 Aug 2017 — USA’s first total solar eclipse since 1979. This eclipse will be the first total solar eclipse visible from mainland United States since 1979. Totality will be visible in many cities from East Coast to West Coast.
http://www.timeanddate.com/eclipse/
A penumbral eclipse occurs when the moon passes through the Earth's penumbra. The penumbra causes a subtle darkening of the moon's surface. A special type of penumbral eclipse is a total penumbral eclipse, during which the Moon lies exclusively within the Earth's penumbra. Total penumbral eclipses are rare, and when these occur, that portion of the moon which is closest to the umbra can appear somewhat darker than the rest of the moon.
https://en.wikipedia.org/wiki/Lunar_eclipse
Lunar eclipses occur when the Moon passes through the Earth's shadow.This occurs only when the Moon is on the far side of the Earth from the Sun, lunar eclipses only occur when there is a full moon. Unlike a solar eclipse, an eclipse of the Moon can be observed from nearly an entire hemisphere.
https://en.wikipedia.org/wiki/Eclipse
August 21, 2017 — Total Solar Eclipse. This eclipse will be the first total solar eclipse visible from mainland United States since 1979. Totality will be visible in many cities from East Coast to West Coast. Eclipse path & animation.
http://www.timeanddate.com/eclipse/
Types of Lunar Eclipses. An eclipse of the Moon (or lunar eclipse) can only occur at Full Moon, and only if the Moon passes through some portion of Earth's shadow. That shadow is actually composed of two cone-shaped components, one nested inside the other.
http://mreclipse.com/Special/LEprimer.html
what is an eclipse of the moon
Lunar eclipses occur when the Moon passes through the Earth's shadow, it is an eclipse of the moon. A lunar eclipse occurs when the Moon passes through the Earth's shadow.