A blue moon—the second full moon to occur in one calendar month—isn’t as rare as the common saying suggests. But on January 31, skygazers will be in for a much rarer lunar event: For the first time in 35 years, a blue moon coincides with a total lunar eclipse, and as a bonus, the moon will seem bigger than usual, TIME reports.
The “super blue blood moon,” as it’s been dubbed, is the result of a perfect storm of celestial conditions. First, it’s the second full moon this month following the first on January 1. Second, the full moon will rise at the part of its monthly orbit that dips closest to Earth, a point called perigee. This causes the moon to appear larger and brighter in the night sky. And finally, all of this is occurring during a total lunar eclipse, which happens when the Earth’s shadow fully blankets the moon.