Tonight will see the full corn moon in the sky in the northern hemisphere but last year it would have been the Harvest moon in September. Here’s why: The Harvest Moon is the only Full Moon name which is determined by the equinox rather than a month.
When the full moon closest to the Autumnal Equinox; the Harvest Moon, happens in October, September’s full Moon becomes the Corn Moon. So Harvest Moon will be the first of two full moons in October 2020 & the second will be considered a blue moon on the 31st October, making a rare appearance on Halloween - So it becomes the Blue Hunters Moon. ( A full Moon on Halloween occurs roughly once every 19 years)
The Hunter's Moon is the full moon following Harvest Moon. The names are recorded from the early 18th century. The Oxford English Dictionary entry for "harvest moon" and "hunter's moon" cites references from the 1700’s.
Blue Moons
For more than half a century, whenever two full Moons appear in a single month (which happens on average every 2 1/2 to 3 years), the second full Moon is called a “Blue Moon.”
another way of categorizing blue moons, and to the Farmers' Almanac, a "blue moon" is the third full moon in any period between either a solstice and an equinox, or between an equinox and a solstice, which contains four full moons.
Since an average lunar cycle is roughly 29½ days, two moons in the same month don't happen very often — usually every two to three years — hence the phrase "once in a blue moon." The extra moon in a month has been called a blue moon for many years, with the earliest recorded use of the term in English dating back to 1528.
Full Moon Names
Full Moons had given names in many ancient cultures. The Full Moon names we use today reflect the changing seasons and nature, like Harvest Moon, Strawberry Moon, or Snow Moon. Many of these names date back to Native Americans of North America. Tribes kept track of the seasons by giving distinctive names to each recurring full Moon. Full Moon names were applied to the entire month in which each occurred. European settlers followed that custom and created some of their own names.
