A Harvest Moon is a full moon that appears closest to the start of Fall (Sept.23). This full moon also happens to land on Friday the 13th, which hasn't happened for nearly two decades. It won't be a big moon like the Super Moon, however. In fact, the moon is at it's furthest from the Earth and will actually look smaller than usual. Best viewing of the Harvest Moon when it is full will be before midnight this Friday the 13th. In many parts of the U.S., the Harvest Moon will appear orange due to the way the light scatters.