What is a Blood Moon/Lunar Tetrad? | Human World | EarthSky
The first Blood Moon eclipse in a series of four is coming up on the night of April 14-15, 2014. This total eclipse of the moon will be visible from the Americas. We in astronomy had not heard the term Blood Moon used in quite this way before this year, but now the term is becoming widespread in the media. The origin of the term is religious, at least according to Christian pastor John Hagee, who wrote a 2013 book about Blood Moons.
Meanwhile, both astronomers and some proponents of Christian prophesy are talking about the upcoming lunar tetrad – the series of four total lunar eclipses – beginning on the night of April 14-15.