Full moons occurring early in September, before the Autumnal Equinox, are called the Corn Moon to distinguish them from a Harvest Moon later in the month when more crops are ready for harvesting. A Corn Moon, by this definition, does not occur every year, but only when it rises before September 20 or thereabouts.

Moon Illusion

A rising full moon often looks larger than it is does later in the evening, even though its image is no larger near the horizon than overhead. Some psychologists have suggested this optical "moon illusion" could be due to the human eye and brain subconsciously comparing its size to foreground objects when close to the horizon.

Prove it to yourself by holding up a pinky finger at arm’s length and using it to totally eclipse the moon when it is near the horizon and when it is overhead.

Nevertheless, the full moons of autumn seem magically bigger and brighter. They rise earlier, leaving a shorter period of darkness between sunset and moonrise.