Story highlights The lunar eclipse is called a "blood moon" by some

The eclipse is due on September 27; believers see it as a sign

(CNN) There will be blood in September -- literally, according to the Internet postings of end-times believers.

The night of September 27-28 will bring a "blood moon." To skywatchers, it simply refers to the copper color the moon takes on during an eclipse, but to some Christian ministers, the fourth and final eclipse in a tetrad -- four consecutive total lunar eclipses, each separated by six lunar months -- fulfills biblical prophecy of the apocalypse. (The first three in the series took place April 15, 2014; October 8, 2014; and April 4, 2015.)

In promotion for his 2013 book "Four Blood Moons," Christian minister John Hagee claimed that the tetrad was a signal being sent by God

"The coming four blood moons points to a world-shaking event that will happen between April 2014 and October 2015," he said.

The reference to the impact is most direct in Joel 2:30-31 , which reads, "And I will show wonders in the heavens and in the earth: Blood and fire and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the coming of the great and awesome day of the Lord."