A full moon is set to light up the night sky on Friday, the first time that’s happened on the West Coast on a Friday the 13th since 2000.
The last time there was a full moon nationwide was on Friday the 13th was Oct. 13, 2000, according to the Farmer’s Almanac. The east coast experienced one on June 13, 2014, though in all other U.S. time zones it happened on June 12.
The rare occurrence won’t happen again nationwide until August 13, 2049.
“It has been calculated that to have a full Moon occur on the 13th day of a particular month, and for that day to be a Friday, it is (on average) a once in 20-year occurrence!” according to the almanac.
This particular full moon is also known as the “Harvest Moon.”
What’s a harvest moon?
A harvest moon is a full moon that usually occurs around the autumnal equinox (September 23, the first day of fall!) but sometimes slides into October in the Western Hemisphere.
A harvest moon rises about 25 minutes after the sun sets in most of the northern United States, NASA said, 25 minutes earlier than a typical moon. This brings extra light in the evenings.
What causes it?
The moon’s positioned at the “most shallow angle” with the eastern horizon, the Farmer’s Almanac said. This shortens the period between the time the sun sets and the moon rises.
And like any full moon, the sun and moon are opposite each other, so the sun cranks up the moon’s brightness.
Why is it called a ‘harvest moon’?
Thank farmers. Those extra 25 minutes of sunlight extended harvesting time for farmers, so they could continue their picking later into the evenings. And at the right time, it kinda looks like a big, glowing pumpkin.
Why is this one special?
It’s mini! This year’s harvest moon will occur during the apogee, or the point in the moon’s orbit when it’s farthest from Earth. As a result, it’ll appear 14% smaller than a typical full moon, the Farmer’s Almanac said.
Why does it look reddish-orange sometimes?
Like the sun when it sets and rises, the moon looks redder the closer to the horizon it gets. That’s because light photons travel through more atmosphere when the moon is at the horizon, compared to overhead. Particles in the atmosphere scatter blue light while letting red light pass through, so the effect is amplified when the moon is at the horizon, according to the Cornell University astronomy department.
When can I see it?
The best time to get a peek is when the micro moon reaches its peak at 12:30 a.m. Saturday. The full harvest moon will rise just after sunset, though.