How to see the full moon on Friday the 13th

A full moon will be visible in the sky this Friday — the first time one has occurred on Friday the 13th in nearly 20 years.

The last time the two events coincided was on Oct. 13, 2000, and it will not happen again until Aug. 13, 2049.

Peak viewing will be at 12:33 a.m. on Saturday morning, but the moon will appear almost entirely full from when the sun goes down Friday evening.

It’s also this year’s “harvest moon” — adding another spooky layer to the already ominous date.

What is a full harvest moon?

The harvest moon is the full moon closest to the autumnal equinox, or the beginning of the fall. This year, the autumnal equinox is on Sept. 23.

Harvest moons are different from other full moons due to the fact that they rise at roughly the same time for several nights running. This weekend’s moon will also appear full on Saturday night, barring any unforeseen weather conditions.

Why the nickname? It arose from farming, as the autumnal equinox often coincided with one of the busiest times of the year for farmers. Crops often rose all at once in late summer and early autumn, meaning they had to work late into the night around this time of year.

And in times of primitive technology, the moon was infinitely more important.

“In the days before tractors with headlights, having moonlight to work by was crucial to getting the harvest in quickly before rain caused it to rot,” Alan MacRobert, an editor at Sky & Telescope magazine, told USA Today.

It’s also a ‘micromoon’

To add yet another unique layer to this year’s harvest moon, it will also appear very small in the sky.

On Friday, the moon reaches “apogee,” meaning it is the farthest point in its orbit around the earth. It will be 252,211 miles from Earth’s center, and therefore will appear 14% smaller to people on Earth than it would at its closest point, according to the Huffington Post.

So, not only will it be a “harvest moon,” it will also be a “micromoon.” By contrast, a “supermoon” occurs when the moon is at the closest point to Earth in its orbit.

Does the harvest moon have any spiritual significance?

Theories abound on the correlation between moon cycles and human behavior. According to Accuweather, the full moon has been associated with “strange or insane behavior, including suicide, sleepwalking and violence.”

And while that may be dismissed as superstitious lunacy, there is science that backs it up. One study, published in the National Criminal Justice Reference Service, showed the “repression of the moon’s gravitational influence brings out social tension, disharmony and bizarre results.”

Another study showed an increase in homicide and aggravated assault around full moons in Florida. (Then again, it is Florida.)

So if you want to see something special Friday night, take a look outside at the moon. Just maybe keep one eye over your shoulder while you’re at it.