The end is nigh.

Sound the alarm; the end of days might be coming! If you believe in Christian apocalypse theory, you might want to get your affairs in order.

In the book of Joel 2:31 (Common English Bible) God says there will be “Wonders in the heavens and in the earth, blood, and fire . . .The sun will be turned to darkness, and the moon to blood before the great and dreadful day of the Lord comes.” And the book of Revelation confirms that during the Great Tribulation, “the moon will become like blood.”         

Pastor John Hagee, author of Four Blood Moons: Something is About to Change, backs off on the prediction of total annihilation, but does suggest celestial signals that are happening now will cause events that “begin in tragedy and end in triumph.”

What is causing all of the alarm is the blood moon that will appear during the upcoming tetrad of lunar eclipses.

A lunar eclipse occurs when the sun, earth and moon align, causing the earth’s shadow to fall on the moon and darken it. During a lunar eclipse, the moon appears blazing red, and is thus called a blood moon. The color results from the refraction of sunlight in the earth’s atmosphere or, more romantically, all of the sunsets and sunrises of the earth.

But this one is special. In fact it is the first of a series of four total lunar eclipses. This unique happening is referred to as a tetrad. The initial lunar eclipse of the series occurs in the early morning hours of April 15, and the subsequent ones fall on Oct. 8, 2014, April 4th, 2015, and Sept. 28, 2015.

Although lunar eclipses average twice a year, not all of them are total eclipses. The other types include penumbral eclipses and partial eclipses, but a tetrad of four total eclipses is notable. During the 20th century, there were only five tetrads, and from 1600 through 1900 there were no tetrads. There will be eight tetrads between 2001 and 2100. They generally occur less often than Blue Moons. 

If you want to catch the lunar eclipse, tune in early Tuesday morning. The eclipse will start a bit before 2 a.m., and totality will occur for over an hour starting at 3 a.m. The event can be seen on the East Coast with your naked eye, although a pair of binoculars can improve the viewing. On that night, there is a bonus astrological anomaly; Mars appears next to the moon. Look for that fiery red star, too!

Pastor Hagee suggests that this tetrad will presage a dramatic occurrence in the Middle East, specifically Israel. He notes that the upcoming tetrad eclipse occurs during the Jewish holidays of Passover and Sukkot and that during past tetrads, events of historical significance have occurred. Ironically, this eclipse can’t be seen from Israel.

Whether you believe that this tetrad will be a fulfillment of biblical prophecies or change the world, I will not dispute its significance, because all by themselves these total lunar eclipses are things of wonder beyond the realm of human affairs.

Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.