“...blue moon...it is the forth full moon in a quarter...”
Is that any three month period, or does it have to be a calendar quarter? Oct 29 will be the 4th full moon in the three month period of Aug, Sep, Oct 2012. Will that be a ‘Blue Moon’?
stormer is correct in post #13. It is the third of four full moons in a three month period...I’m guessing on that last...but the calender is derived from the planet’s motion, not the moon’s. The term exists only because we attempt to meld the two.