'Blue Moon' Lights Up the Sky Tonight: See It Live in Slooh Webcast

'Flower Moon' by Greg Diesel Walck
Astrophotographer Greg Diesel Walck sent in a photo of the full moon rising over Bells Island, NC, on May 15, 2014. (Image credit: Greg Diesel Walck/www.facebook.com/GregDieselPhotography)

Blue Moon will rise Saturday night (May 21), and you can watch it with expert commentary online during a live Slooh webcast from the Institute of Astrophysics of the Canary Islands.

The free program is a collaboration between the online Slooh Community Observatory and "The Old Farmer's Almanac," and will run from 8 to 8:30 p.m. EDT (0000 to 0030 GMT on Sunday, May 22). You can follow the Slooh webcast at Slooh.com

You can also watch the Blue Moon webcast on Space.com, courtesy of Slooh.

Thought to be called "blue" after an old english term meaning "betrayer," a Blue Moon is an extra full moon that occurs due to a quirk of the calendar. [See the full Blue Moon Infographic here.] (Image credit: Karl Tate, SPACE.com)

Saturday's Blue Moon won't actually appear blue. Instead, the term Blue Moon refers to the third full moon in a season that features four full moons, rather than of the typical three. Blue Moons occur about once every 2.7 years. The second full moon in a calendar month is commonly considered a Blue Moon, but that rule doesn't always hold up. For instance, this is the first full moon of May, but it is still a Blue Moon. [Blue Moon Photos of 2015: Amazing Full Moon Views]

Saturday's full moon is known as the Full Flower Moon, heralding the arrival of summer flowers. It is also known as the Full Corn Planting Moon and the Milk Moon. Slooh's live broadcast will discuss the origin of the moon's name, how to calculate a Blue Moon and how the moon's location was once key evidence in a murder trial, Slooh representatives said in a statement. Viewers also can go to Slooh.com to watch the broadcast, snap and share photos during the event, personally control Slooh's telescopes, and interact with the webcast hosts and audience members.

"This webcast marks the newest installment in a partnership between Slooh and'The Old Farmer's Almanac,' with a mission to connect each other's audiences to the miraculous ebb and flow of nature as caused by celestial bodies; moments of wonder we all take for granted but are no less delighted to be exposed to again and again," they said in the statement.

Editor's note: While May's Blue Moon won't actually be blue in color, it will still be a spectacular sight. So if you snap an amazing photo of the full moon Saturday and would like to share it with Space.com and our news partners for a possible story or image gallery, send images and comments to managing editor Tariq Malik at spacephotos@space.com.

Email Sarah Lewin at slewin@space.com or follow her @SarahExplains. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

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Sarah Lewin
Associate Editor

Sarah Lewin started writing for Space.com in June of 2015 as a Staff Writer and became Associate Editor in 2019 . Her work has been featured by Scientific American, IEEE Spectrum, Quanta Magazine, Wired, The Scientist, Science Friday and WGBH's Inside NOVA. Sarah has an MA from NYU's Science, Health and Environmental Reporting Program and an AB in mathematics from Brown University. When not writing, reading or thinking about space, Sarah enjoys musical theatre and mathematical papercraft. She is currently Assistant News Editor at Scientific American. You can follow her on Twitter @SarahExplains.