Have you noticed the moon lately? It’s been lovely the last few nights, but it was officially full Monday at 11:52 p.m. ADT.
Now, that giant orb in the sky wasn’t your “garden variety” full moon, but the famous Harvest Moon.
Each month the full moon comes with a few names – usually tied to the activities of the month. For example, the Full Strawberry Moon in June – the time the local strawberries are ready to be picked.
The full moon in September can be the Full Corn Moon – unless it is the full moon closest to the fall equinox; that full moon is always the Harvest Moon. The Harvest Moon is the only full moon name which is determined by the equinox rather than a month.
The full moon nearest the equinox is special for another reason and that’s called the Harvest Moon Effect.
The usual behaviour of the moon is to rise an average of 50 minutes later each night. This happens because the moon's orbital motion, combined with the larger orbit of the Earth around the sun, carries it farther eastward among the constellations of the zodiac from night to night. Around the date of the Harvest Moon, the moon rises as little as 23 minutes later on successive nights, and there is an abundance of bright moonlight early in the evening. Before tractors with headlights, this moonlight allowed farmers to continue to harvest their crops after the sun set... at least for a few days. By the time the moon has reached last quarter, the typical 50-minute delay has returned.
Some people have asked me what makes the Harvest Moon appear orange? It doesn’t always but because this full moon's path around Earth creates a narrow angle with the horizon, the moonlight travels through more clouds and dust close to the horizon. The light bounces off the particles in the air and the moon can look like a big fall pumpkin in the sky.