So here you have two definitions of a blue moon but the one for a calendar blue moon does not describe the true meaning of a blue moon. Here's why:
Phases of the Moon. The moon cycles 13 times a year through phases, each of which influence us just like the pull of the tides. It starts with the New Moon, which carries the energy of new beginnings, this is a great time to focus on stepping into something new. Then the Full Moon, Signifies the time of the completion of a project, and finally returns to the New Moon again. This entire cycle occurs over a period of 28 days, and yes, there is no mistaking it, this is the same as women's menstrual cycles, women tend to be much more connected to the moon than men.
However, the astronomers will require more HST observations in order to obtain accurate measurements in order to determine if the moon's orbit is circular or elliptical. Preliminary estimates suggest that if the moon is in a circular orbit, it finishes a circle around Makemake in 12 days or longer.