http://www.newsweek.com/when-next-blood-moon-total-lunar-eclipse-supermoon-1592152 > Later this month, an extra special full moon is set to grace the skies above the Earth. > Full moons occur roughly once a month, when the Earth is located directly between the sun and the moon. Technically, the moon turns full at a specific moment, however, it will appear fully illuminated for around a day either side of this time.