A supermoon is a full moon that comes within 90 percent of the perigee, the closest point in its elliptical orbit to Earth, and a blue moon refers to the presence of multiple full moons in a given period. A seasonal blue moon is the third full moon in a season that has four, and a monthly blue moon is the second full moon within the same calendar month. This time around, it is a seasonal blue moon we're looking at. Join CGTN and take in the fantastic view of the blue supermoon.