It hasn’t happened in over 30 years and it won’t happen again for 10 years. Mark your calendars for Sunday, Sept. 27 when a super moon lunar eclipse will happen.

So, what does a super moon mean? NASA scientist Noah Petro says, “The orbit of the moon is not a perfect circle, the moon is sometimes closer to the Earth than at other times during its orbit.”

The moon is not huge, but it is a little larger than normal to the naked eye.

The total eclipse will start at 7:07 p.m. mountain time on Sunday evening and will last until just before 11 p.m., start to finish. It will be visible across North and South America, Europe, Africa, and parts of West Asia and the eastern Pacific.