This double-exposure photo shows the blue supermoon above the Bell Tower in Xi'an, Shaanxi Province on August 30, 2023. /CFP

This double-exposure photo shows the blue supermoon above the Bell Tower in Xi'an, Shaanxi Province on August 30, 2023. /CFP

A plane flies across the blue supermoon in Dalian, Liaoning Province on Wednesday, August 30, 2023. /CFP

A plane flies across the blue supermoon in Dalian, Liaoning Province on Wednesday, August 30, 2023. /CFP

The blue supermoon is seen over a drum tower in Congjiang County, Guizhou Province on August 30, 2023. /CFP

The blue supermoon is seen over a drum tower in Congjiang County, Guizhou Province on August 30, 2023. /CFP

A blue supermoon is observed over the Grand Tang Mall in Xi'an, Shaanxi Province on Wednesday, August 30, 2023. /IC

A blue supermoon is observed over the Grand Tang Mall in Xi'an, Shaanxi Province on Wednesday, August 30, 2023. /IC

A blue moon is not blue. The full moon on Wednesday was the second full moon of the month, which makes it a blue moon. And it was a supermoon too, which happens when the moon is full during the closest point of its elliptical orbit around Earth (also called "perigee"). This rare astronomical phenomenon was observed in many places across China on Wednesday night, forming beautiful views over the nocturnal autumn landscapes. The next blue supermoon will take place in 2037.