The Moon In January 
Image Credit: WFI Team, ESO, MPI-A, OAC 

Perhaps only in recent times, the term "Blue Moon" has come to mean the second Full Moon in a month, joining a list of folklore names for the brightest lunar phase. Aren't Blue Moons extremely rare? Well, the Moon's phases repeat every 29.5 days and most months have 30 or 31 days, so a Blue Moon is certainly possible if not a common event. In fact, the last Blue Moon in 1999 occurred in March, leaving February without a Full Moon at all.  This sharp telescopic view of a waning crescent Moon was recorded on January 12th by the European Southern Observatory's new WFI camera.

You can find this photo and other exciting images on the Astronomy Picture of the Day web site. Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.