Referred to by many as a 'blue moon'
"While dust particles in the atmosphere can in fact make the moon at times appear blueish, the term "blue moon," which has a somewhat confusing history, generally refers to the second full moon in a calendar month. And they occur more frequently than the phrase "once in a blue moon" might have you believe: every 2.7 years. The last one happened to fall on New Year's Eve 2009." via Newser and space.com Picture by gkr in Gallnas,Dalsland