Super Blue Blood Moon January 31st, 2018. Visible in the western hemisphere for the first time in 152 years. The U.S. won't see another super blue blood trio until 2037. The second full moon of the calendar month is called a blue moon. It is called a supermoon because it's especially close to the Earth, making it appear larger and brighter than usual. It was also a total lunar eclipse. That's why this is also called a blood moon As the moon makes this close, full moon approach to the Earth, it's going to pass through the Earth's shadow and the Earth's shadow is going to cause the moon to appear a deep red color.