A lunar eclipse can occur at very different frequencies. For a lunar eclipse to happen, the planets are required to be in line a certain way. Due to the requirements, a lunar eclipse can happen sporadically. Normally, they happen in a group and then stop for awhile and then happen again. You can find more information here: http://www. souledout. org/nightsky/eclipsefrequency/eclipsefrequency. html
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How Often Does a Lunar Eclipse Occur
A lunar eclipse occurs when the Moon passes directly behind the Earth, preventing the Sun's rays from reaching it. Lunar eclipses only occur at full moon and when the Moon is in the Earth's plane of orbit.
Lunar eclipses usually occur a few times a year.