Why it's called the Corn Moon
September's full moon is the Corn Moon, marking the point when corn — maize — was ready to bring in. In most years it also earns the more famous title Harvest Moon: the full moon nearest the autumn equinox, whichever month it lands in.
The Corn Moon in the sky
The Harvest Moon effect is real astronomy: around the equinox, the moon's path makes a shallow angle with the horizon, so for several evenings running the full moon rises only shortly after sunset — continuous light that once let farmers work the fields late.
What the Corn Moon means
This is the moon of results. Whatever the year's cycle was growing is now either in the barn or it isn't. In moon practice the Corn Moon is for gathering, finishing and honest accounting — gratitude included.