'Blue moon' to shine Friday night

(ANSA) - Rome, July 31 - A rare full moon will appear in the skies on Friday night, known as a 'blue moon', Italian amateur astronomers union UAI said.
    This does not mean the moon will appear blue, but that it is the second full moon to appear this month after the first one on July 2.
    This type of "blue moon" occurs roughly every two to three years. The last one was in August 2012 and the next one will be in January 2018. "The moon will be its usual colour, so watch out for blue moon hoax pictures that often appear online," warned Paolo Volpini from UAI.
    The moon is due to be visible in the sky from about 20:19.