There is a uncommon astronomical outcome happening on Friday , May 19 that you wo n’t be able to see . It ’s a new Moon , the lunar stage where the Moon is not visible to us because the Moon is on the day side . Friday ’s one is a rarity because it is an extra new Moon this season , making the so - visit Black Moon the new Moon equivalent of a Blue Moon .
supernal rhythms do n’t utterly align . The Moon goes around the Earth 12.37 times every year , So while it is a estimable estimation to say that there is a full Moon and a new Moon every month , we end up having extras . These extras are , in non - astronomical terminus , get it on as Black and Blue Moons . They fall out on average every two or three years . A more accurate time value is there are seven extra new Moons within the 235 new moons that happen in almost exactly 19 days . This is known as the Metonic Cycle , which is the base of manylunar calendars .
What is a Blue Moon?
The Moon ’s phases have traditionally been used to know when to plant and harvest time . The terminal figure " Blue Moon " does not rise in astronomical circles but from the 1937 variant of the Maine Farmer ’s Almanac . These day it refers to two scenario . One is the third full Moon in a season with four full Moon . Seasons usually have three months and so three Moons . In season with four moonlight , the third one is know as the Blue Moon .
The second significance refers to the second full Moon in a month , and was create by accident . A misunderstanding of the original Almanac reference book by J.H. Pruitt in a 1946 variation of the American magazineSky and Telescope trace it as being the second full Moon in a month , a definition that is still very democratic .
What is a Black Moon?
The terminal figure " Black Moon " is far more late – originate in Wiccan and astrological R-2 in the last decennium – and , like a Blue Moon , does n’t have a individual definition . Astrologyaside , it is often referred to as a mirror variation of the Farmer ’s Almanac ’s Blue Moon , so the third new Moon of a time of year . This is the type of Black Moon that is occurring this Friday and occurs around once every 33 months .
consort toTimeandDate.com , it can also mention to the second New Moon in a month , which occurs roughly every 29 months and is somewhat more unwashed .
In either case , the Moon does not change colour . It is neither blue nor black ( orpinkfor that matter ) . It does however present good sky viewing opportunities as the Nox sky is not contaminate with the bright light of a full Moon , so if you want to get any last remaining Eta Aquarids , now is a good time to look up . So , enjoy not seeing the spectacle on Friday regardless of your preferred definition .
