The September full moon, traditionally known as the "Corn Moon", "Barley Moon" and "Harvest Moon", will occur after midnight on Friday, September 13 for the most of North America, and on September 14 for much of the rest of the world. So, what is a Harvest Moon?
This one always shines in or neat the stars of Aquarius and Pisces. Full moon always rise around sunset and set around sunrise. Because this the closest full moon to the autumnal equinox in 2019, it is also the Harvest Moon. On the evenings around its full phase, the moon usually rises about 50 minutes later on each consecutive night. But the shallowly sloping evening ecliptic around the equinox causes Harvest Moons to rise at almost the same time each night - only delayed by as little as 10 minutes, depending on your latitude.
This phenomenon traditionally allowed farmers to work into the evening under bright moonlight-hence the name. It also means that if you arrive home from work or walk the dog at the same time every evening, you might notice the "full" moon for several days in a row. The effect is stronger the farther from equator you live. The moon behaves the same way in the Southern Hemisphere - but six months later, at its own autumnal equinox. By the way - this full moon will occur only 14 hours after apogee, the moon's farthest point from Earth. As a result, it could be considered a Punymoon or Micromoon (the opposite of a Supermoon). It'll appear slightly less large and bright than an average full moon.
Its quite rare for a full moon to appear on Friday the 13th. The last time it occurred on Oct. 13, 2000, and won't happen again until Aug. 13, 2049.
