--- ---  # See an Incredible Photo of Friday Night's Blue Moon by [Eliza Gray](https://time.com/author/eliza-gray/) ## Eliza Gray Aug 1, 2015 1:58 PM UTC  A full moon, known as the Blue Moon, is seen next to the Statue of Liberty in New York on July 31, 2015. A full moon, known as the Blue Moon, is seen next to the Statue of Liberty in New York on July 31, 2015.Eduardo Munoz—Reuters by [Eliza Gray](https://time.com/author/eliza-gray/) ## Eliza Gray Aug 1, 2015 1:58 PM UTC The second full moon of July rose Friday night, a phenomenon referred to as a “blue moon.” Though the phrase “once in a blue moon” is meant to describe a rare event, a blue moon is neither rare, or blue. “Blue moon” is actually a term used to describe the second full moon in a single calendar month. Most years only have 12 moons, but this year has 13, which happens every two to three years, according to astronomers. “Blue moons” don’t actually appear blue, but the moon can appear blue after events on earth like wildfires and volcanic eruptions, according to [NASA](http://science.nasa.gov/science-news/science-at-nasa/2015/27jul%5Fbluemoon/). ### PHOTOS: 20 Breathtaking Images of Earth From Space  Aleppo, Syria, May 26, 2013 – The Citadel of Aleppo – medieval fortified palace DigitalGlobe—Getty Images  Belfast, Northern Ireland, Nov. 3, 2013 – “Wish,” a large-scale art work DigitalGlobe—Getty Images  Utah, USA, April 22, 2013 – Colorado River DigitalGlobe—Getty Images  Cuanza River, Angola, April 28, 2013 – Cambambe Dam DigitalGlobe—Getty Images  Doha, Qatar, March 4, 2013 – Artificial island spanning nearly four million sq meters. DigitalGlobe—Getty Images  Dunalley, Australia, Jan. 6, 2013 – fires, false color image (red = healthy vegetation) DigitalGlobe—Getty Images  Australia, April 22, 2013 – Great Barrier Reef DigitalGlobe—Getty Images  Gwadar coast, Pakistan Sept. 29, 2013 – new island created by earthquake in Pakistan DigitalGlobe—Getty Images  Croatia, Feb. 16, 2013 – Galešnjak (Island of Love) DigitalGlobe—Getty Images  Hong Kong, China May 9, 2013 – giant rubber duck DigitalGlobe—Getty Images  Madang Province, Papua New Guinea, March 22, 2013 – Manam Volcano DigitalGlobe—Getty Images  Namib Desert, Namibia, May 13, 2013 – Sossusvlie area DigitalGlobe—Getty Images  Naples, Italy, Feb. 19 2013 – Mount Vesuvius DigitalGlobe—Getty Images  Niger, Feb. 13, 2013 – Arlit Uranium Mine DigitalGlobe—Getty Images  Schooner Cays, Bahamas, May 26, 2013 DigitalGlobe—Getty Images  Sochi, Russia, March 17, 2013 – Site of 2014 winter Olympics DigitalGlobe—Getty Images  Near the city of Sur, Oman, Feb. 13, 2013 – massive “green tide” DigitalGlobe—Getty Images  Valencia, Spain, July 19, 2013 – Palau de les Arts Reina Sofia and Gulliver Park with an enormous fiberglass model of Lemuel Gulliver trapped DigitalGlobe—Getty Images  Versailles, France, Aug. 20, 2013 – Palace of Versailles DigitalGlobe—Getty Images  Xi'an, China, Sept. 24, 2013 – Shiyuan Park DigitalGlobe—Getty Images Blue Moon: See an Incredible Photo From Friday Night ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/3981125/blue-moon-photo/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/3981125/blue-moon-photo/"},"headline":"See an Incredible Photo of Friday Night's Blue Moon","datePublished":"2015-08-01T13:58:16.000Z","dateModified":"2026-05-11T04:47:10.889Z","description":"It usually happens just once every couple of years","url":"https://time.com/3981125/blue-moon-photo/","keywords":["astronomy","Newsfeed"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/blt7fdfc16e95285b4c/69885d6ecd1bbae6346fc8bf/blue-moon.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Eliza Gray","jobTitle":null,"url":"https://time.com/author/eliza-gray/"}],"articleSection":"Science","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/blt7fdfc16e95285b4c/69885d6ecd1bbae6346fc8bf/blue-moon.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"blue moon statue liberty new york","caption":"blue moon statue liberty new york","creditText":"Eduardo Munoz—Reuters","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/science/","name":"Science"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/astronomy/","name":"astronomy"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/3981125/blue-moon-photo/","name":"See an Incredible Photo of Friday Night's Blue Moon"}}]}] ```