Blue Moons: myths, facts, history, and dates Second full moon in month May 2016 Third full moon in a season of four full moons Although the full moon on July 31, 2015, will look like an ordinary full moon, it's actually a bit extraordinary—a blue moon. What is a Blue Moon? There are in fact two definitions for a blue moon. According to the more recent definition, a blue moon is the second full moon in a calendar month. For a blue moon to occur, the first of the full moons must appear at or near the beginning of the month so that the second will fall within the same month (the average span between two moons is 29.5 days). The Other Kind of Blue Moon The older definition, which is recorded in early issues of the Maine Farmer's Almanac, states that the blue moon is the third full moon in a season that has four full moons. The full Moon in May 2016, will be this type of blue moon. Why would one want to identify the third full moon in a season of four full moons? The answer is complex, and has to do with the Christian ecclesiastical calendar .

Some years have an extra full moon—13 instead of 12. Since the identity of the moons was important in the ecclesiastical calendar (the Paschal Moon, for example, used to be crucial for determining the date of Easter ), a year with a 13th moon skewed the calendar, since there were names for only 12 moons. By identifying the extra, 13th moon as a blue moon, the ecclesiastical calendar was able to stay on track. For more background information on the controversy over the two definitions of blue moon, see the Sky and Telescope article, "What's a Blue Moon?" In it they explain how the two different definitions of a blue moon came about—including their own role in introducing the second, modern definition. A Star Rating for the Modern Blue Moon Although Sky & Telescope calls the modern blue moon definition "trendy" and a "mistake," the fact that there is an older, preexisting (and more complicated) definition does not necessarily make it the more interesting or meaningful definition. Charting the "third full moon in four full moons" in a season isn't everyone's idea of an fascinating enterprise.

The modern, "trendy" definition, however, points to an intriguing astronomical phenomenon—every so often two moons can manage to position themselves in the same month. Given that full moons occur once every 29.5 days, this is quite an accomplishment! How Often Does a Blue Moon Occur? Over the next 20 years there will be about 15 blue moons, with an almost equal number of both types of blue moons occurring. No blue moon of any kind will occur in the years 2011, 2014, and 2017. The more recent phenomenon, where the blue moon is considered to be the second full moon in a calendar month, last occurred on August 31, 2012. Two full moons in one month may occur in any month out of the year except for February, which is shorter than the lunar cycle. The other, older blue moon event, which happens when there are four full moons in a season, last occurred Aug. 21, 2013.

Since this type of blue moon is reckoned according to the seasons, it can only occur in February, May, August, or November, about a month before the equinox or the solstice. Twice in a Blue Moon The rare phenomenon of two blue moons (using the more recent definition) occurring in the same year happens approximately once every 19 years. 1999 was the last time a blue moon appeared twice, in January and March. The months of the double blue moons are almost always January and March. That is because the short month that falls in between them, February, is a key ingredient in this once-every-19-year phenomenon. For January and March to each have two full moons, it's necessary for February to have none at all. Since February is usually 28 days long, and the average span between full moons is 29.5 days, if a full moon occurs at the end of January, it's possible for the next full moon to skip February entirely and fall in the beginning of March. Once in a Blue Moon "Blue moon" appears to have been a colloquial expression long before it developed its calendrical senses.

According to the Oxford English Dictionary, the first reference to a blue moon comes from a proverb recorded in 1528: If they say the moon is blue, We must believe that it is true. Saying the moon was blue was equivalent to saying the moon was made of green (or cream) cheese; it indicated an obvious absurdity. In the 19th century, the phrase until a blue moon developed, meaning "never." The phrase, once in a blue moon today has come to mean "every now and then" or "rarely"—whether it gained that meaning through association with the lunar event remains uncertain. Did you know? Once in a Blue Moon | Science Mission Directorate Science Mission Directorate Once in a Blue Moon Space Science News home "Once in a Blue Moon" For the first quarter of 1999, it means 'two-thirds of the time.' February 26, 1999: We've all heard the saying "it happens only once in a blue moon," generally used to describe an uncommon occurance.

But for the first quarter of 1999, using the phrase "once in a blue moon" could also mean "two out of three times." Right: Artist Duane Hilton's portrayal of the March 1999 "Blue Moon" as viewed between White Bark pine trees in California's Eastern Sierra. In astronomical terms, a 'blue moon' really doesn't have anything to do with color. Instead, it is the term used to denote the second full moon that occurs within a given calendar month. Because it takes the moon about 29 days to circle the Earth once in its orbit, it is possible that two full moons can occur within the same calendar month. Such was the case in January 1999, when the moon was full on the 2nd and the 31st, making the full moon on the 31st a 'blue moon.' On average, this takes place once every two and a half years. This time, however, we don't have to wait over 2 years for another blue moon. A second blue moon will appear this March, with the moon displaying its full-phase on the 2nd and the 31st of March.

Recent Headlines November 30: Learning how to make a clean sweep in space Although a 'blue moon' doesn't really look blue, there have been times when the moon does seem to have a blue color. This can be caused by dust particles in the atmosphere, which scatter light. The effects of this dust on the light coming from the moon can cause it to appear bluish in color. Fine dust particles are ejected into the Earth's upper atmosphere after large volcanic eruptions, for example. The eruption of the Krakatoa volcano in 1883 gave us one such 'blue moon'. For about 24 months after this volcano exploded, the dust it spewed into the upper atmosphere caused the moon to appear green and blue when viewed from around the world. Sign up for our EXPRESS SCIENCE NEWS delivery There is little scientific significance to either an astronomical blue moon or a bluish-looking moon. But astronomers are interested in how the moon reflects different colors. The moon generates no light of its own, but reflects light from the Sun. By studying how the moon reflects this light, scientists can explore the chemical composition of the lunar surface. Right: A Violet Moon.

Checking out the Galileo spacecraft's cameras during its December 1992 flyby of Earth's Moon, controllers took this dramatically illuminated picture through a violet filter. The view looks down on the Moon's north polar region with the Sun shining from the left at a low angle and the direction toward the moon's North pole toward the lower right. More information. Studying the moon can be tricky, because the moon is too bright to be photographed with large, highly sensitive telescopes on the ground or with the Hubble Space Telescope. The moon's brightness can potentially damage such sensitive optical instruments. Less sensitive telescopes on the ground and on satellites, however, have given us some stunning images of the full moon. The moon can also be photographed using different light wavelengths, such as ultraviolet. Above: An Ultraviolet Moon. One of the more interesting space-based images obtained of the moon was taken from the Astro-2 observatory, lofted aboard the space shuttle in 1995. Although the moon appears blue in both images, the left-hand image is actually taken in the ultraviolet, which is higher in energy than blue or violet light.

The oddity of having two blue moons within three months is not of much interest to scientists, but it is a notable event to many others. Ever charming and compelling, the blue moon will likely continue to serve as inspiration for songwriters and poets for generations to come. Web Links Blue Moon | Science Blue Moon Created on Monday, 27 July 2015 11:26 | Written by Steve Owens Blue Moon This Friday 31 July 2015 there is an event which happens only "once in a blue moon". Literally. This month there is a Blue Moon. The occurrence of a Blue Moon doesn't mean that the Moon will in fact turn blue. Instead a Blue Moon refers to a second Full Moon occurring within a fixed amount of time. There are two widely accepted definitions of a Blue Moon: either it is an additional Full Moon within a season, or an additional Full Moon within a calendar month. Moon Phases Normally there are twelve Full Moons in a year, with one occurring every month. In fact the word "month" is derived from "Moon". However the phases of the Moon don't divide the year perfectly into 12 with no left overs.

In fact there are 12.37 Full Moons every year, and for this reason, every so often, we get 13 Full Moons in a year, which means an extra one in a season or in a calendar month. The Maine Farmers' Almanac Blue Moon (Type 1) The original definition of the Blue Moon came from the Maine Farmers' Almanac which defined a Blue Moon as the third Full Moon within a quarter-year season that has four Full Moons. Confused? You're not alone. Normally a quarter-year season will have three Full Moons in it, as normally there are 12 Full Moons in a year. But due to that extra Full Moon that we sometimes get, every so often there are 13 Full Moons in a year. This extra Full Moon will occur in one specific season, and in that season the third of the four Full Moons is known as the Blue Moon. For decades this definition of a Blue Moon held and was the only one. However now we have an alternative definition, thanks to a mistake in a prominent astronomy magazine.

The Sky and Telescope Blue Moon (Type 2) In 1946 the astronomy magazine Sky and Telescope published an article by James Hugh Pruett in which he mistakenly interpreted the Maine Farmers' Almanac. He correctly stated that due to the 12.37 Full Moons per year, we get an extra (thirteenth) Full Moon in seven years out of every 19. He then went on to state that the extra Full Moon that occurs in these seven years must occur in a specific month (correct) and that the second Full Moon in a calendar month is known as the Blue Moon (incorrect, according to the original definition). Despite the fact that this definition of a Blue Moon was a mistake at the time, it was widely adopted, probably in large part due to its relative simplicity, and is the one that most people use these days. This Month's Blue Moon This Friday's Blue Moon is an example of a Type 2 Blue Moon, the second Full Moon within a calendar month (July 2015).

The first Full Moon this month occurred on 2 July, leaving ample time for the second Full Moon to sneak in at the end of the month, on Friday 31 July 2015. A Type 2 Blue Moon occurs on average once every 2.7 years. Most type 2 Blue Moons occur within months of 31 days, but they can occur in 30-day months. Within any given century you can expect 37 Blue Moons, around 33 of which will occur in a 31-day month, and around seven of which will occur in a 30-day month. Future Blue Moons After this week's Blue Moon the next one won't occur until 2018, but we get two that year! The first occurs on 31 January 2018 (Full Moons on 2 and 31 January 2018) and the second on 31 March 2018 (Full Moons on 2 and 31 March 2018). After that we have to wait until 31 October 2020.

The next Blue Moon to occur in a 30-day month happens on 30 September 2031. What is a Blue Moon? | Astronomy Essentials | EarthSky What is a Blue Moon? By Bruce McClure and Deborah Byrd in Astronomy Essentials | May 16, 2016 The next Blue Moon (second full moon in one calendar month) will be on January 31, 2018. Most Blue Moons are not blue in color. This photo of a moon among fast-moving clouds was created using special filters. Image via EarthSky Facebook friend Jv Noriega. In recent years, people have been using the name Blue Moon for the second of two full moons in a single calendar month. An older definition says a Blue Moon is the third of four full moons in a single season. Someday, you might see an actual blue-colored moon. The term once in a blue moon used to mean something rare. Now that the rules for naming Blue Moons include several different possibilities, Blue Moons are pretty common! The next Blue Moon (second full moon in one calendar month) will be on January 31, 2018.

Follow the links below to learn more about Blue Moons: Can there be two Blue Moons in a single calendar year? Desert Blue Moon from our friend Priya Kumar in Oman. August, 2012. Thank you, Priya! Blue Moon as third full moon of four in a season. The Maine Farmer’s Almanac defined a Blue Moon as an extra full moon that occurred in a season. One season – winter, spring, fall, summer – typically has three full moons. If a season has four full moons, then the third full moon may be called a Blue Moon. There was a Blue Moon by this definition happened on November 21, 2010 . Another occurred on August 20-21, 2013. It last happened on May 21, 2016, and – on that night – the moon was near the red planet Mars! On the night of May 21, 2016, many will call the moon a Blue Moon. It’ll be blue in name only. But on that night, something cool is happening. The moon will be near red Mars, now nearly at its closest for this two-year period!

May 21 Blue Moon was near red Mars. This full Blue Moon and the red planet Mars shone together all night long, from dusk May 21 until dawn May 22. Of course, the moon will be blue in name only. But red Mars will really be noticeably reddish in color, and the full moon and Mars are guaranteed to be spectacular to view on this date. Earth passed between Mars and the sun on May 22. Astronomers call that an opposition of Mars , because Mars was opposite the sun, rising at sunset. Likewise a full moon rises at sunset. And that’s why Mars was near the moon on May 21, when the moon is full and Mars is just one day from opposition . This photo was created using special blue filters, too. Image via EarthSky Facebook friend Jv Noriega. The next monthly Blue Moon (third of four full moons in one season) will take place on May 18, 2019. Next monthly Blue Moon on January 31, 2018. In recent decades, many people have begun using the name Blue Moon to describe the second full moon of a calendar month.

There was a full moon on July 2, 2015. There was another full moon on July 31, 2015. So the July 31, 2015, full moon was called a Blue Moon, according to this definition. The next one will be on January 31, 2018. The time between one full moon and the next is close to the length of a calendar month. So the only time one month can have two full moons is when the first full moon happens in the first few days of the month. This happens every 2-3 years, so these sorts of Blue Moons come about that often. The idea of a Blue Moon as the second full moon in a month stemmed from the March 1946 issue of Sky and Telescope magazine, which contained an article called “Once in a Blue Moon” by James Hugh Pruett. Pruett was referring to the 1937 Maine Farmer’s Almanac, but he inadvertently simplified the definition. He wrote: Seven times in 19 years there were — and still are — 13 full moons in a year.

This gives 11 months with one full moon each and one with two. This second in a month, so I interpret it, was called Blue Moon. Had James Hugh Pruett looked at the actual date of the 1937 Blue Moon, he would have found that it had occurred on August 21, 1937. Also, there were only 12 full moons in 1937. You need 13 full moons in one calendar year to have two full moons in one calendar month. However, that fortuitous oversight gave birth to a new and perfectly understandable definition for Blue Moon. EarthSky’s Deborah Byrd happened upon a copy of this old 1946 issue of Sky and Telescope in the stacks of the Peridier Library at the University of Texas Astronomy Department in the late 1970s. Afterward, she began using the term Blue Moon to describe the second full moon in a calendar month on the radio.

Later, this definition of Blue Moon was also popularized by a book for children by Margot McLoon-Basta and Alice Sigel, called “Kids’ World Almanac of Records and Facts,” published in New York by World Almanac Publications, in 1985. The second-full-moon-in-a-month definition was also used in the board game Trivial Pursuit. Today, it has become part of folklore. What most call a Blue Moon isn't blue in color. It's only Blue in name. This great moon photo from EarthSky Facebook friend Rebecca Lacey in Cambridge, Idaho. Which Blue Moon definition is better? In recent years, a controversy has raged – mainly among purists – about which Blue Moon definition is better. The idea of a Blue Moon as the third of four in a season may be older than the idea of a Blue Moon as the second full moon in a month. Is it better? Is one definition right and the other wrong? Opinions vary, but, remember, this is folklore. So we, the folk, get to decide. In the 21st century, both sorts of full moons have been called Blue.

As the folklorist Phillip Hiscock wrote in his comprehensive article Folklore of the Blue Moon : Old folklore it is not, but real folklore it is. Can a moon be blue in color? There’s one kind of blue moon that is still rare. It’s very rare that you would see a blue-colored moon, although unusual sky conditions – certain-sized particles of dust or smoke – can create them. Blue-colored moons aren’t predictable. So don’t be misled by the photo above. The sorts of moons people commonly call Blue Moons aren’t usually blue. For more about truly blue-colored moons, click here . Enjoying EarthSky so far? Sign up for our free daily newsletter today! Can there be two Blue Moons in a single calendar year? Yes. It last happened in 1999. There were two full moons in January and two full moons in March and no full moon in February. So both January and March had Blue Moons. The next year of double monthly blue moons is coming up in January and March, 2018 – and then, after that, in January and March, 2037.

Very rarely, a monthly Blue Moon (second of two full moons in one calendar month) and a seasonal Blue Moon (third of four full moons in one season) can occur in the same calendar year. But for this to happen, you need 13 full moons in one calendar year AND 13 full moons in between successive December solstices. This will next happen in the year 2048, when a monthly Blue Moon falls on January 31, and a seasonal Blue Moon on August 23. Bottom line: A blue-colored moon is rare. But folklore has defined two different kinds of Blue Moons, and moons that are Blue by name have become pretty common. A Blue Moon can be the second full moon in a month. We had that sort of Blue Moon on July 31, 2015, and will happen again on January 31, 2018. Or it can be the third of four full moons in a season. That’ll be May 18, 2019.

CNN.com - Once in a blue moon - Jul 30, 2004 Once in a blue moon By Joe Rao SPACE.com An image of how the moon might appear when a bluish cast is caused by soot or particles in the air. RELATED ( SPACE.com ) -- Some almanacs and calendars assert when two full moons occur within a calendar month, that the second full moon is called the "Blue Moon." That second full moon this month will come on Saturday, July 31st, and will look no different than any other full moon. On past occasions, usually after forest fires or volcanic eruptions, the moon can indeed take on a bluish or lavender hue. Soot and ash particles, deposited high in the Earth's atmosphere can sometimes make the moon appear bluish. Such a situation was noted across eastern North America in late September 1950, due to smoke from widespread forest fire activity in western Canada. Also, in the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were reports of blue moons worldwide. The phrase "Once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, perhaps even rare.

Yet, to have two full Moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 32 months. And in the year 1999 it actually occurred twice in three months. For the longest time no one seemed to have a clue as to where the "Blue Moon Rule" originated. I myself once suggested that the rule might have evolved out of the fact that the word "belewe" came from the Old English, meaning, "to betray." Perhaps, I suggested, the second full Moon is 'belewe' because it betrays the usual perception of one full moon per month. It was not until the year 1999 that the origin of the calendrical term "Blue Moon" was at long last discovered.

It was during the time frame from 1932 through 1957 that the Maine Farmers' Almanac suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, the third should be called a "Blue Moon." But thanks to a couple of misinterpretations of this arcane rule, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 syndicated radio program, it now appears that the second full Moon in a month is the one that's now popularly accepted as the definition of a "Blue Moon." Another interesting fact about the full moon of July 2nd is its near coincidence with the time of perigee -- its closest point to the Earth. Perigee occurred on July 1st at 7:00 p.m. EDT; the moment of full moon comes just over a half a day later at 7:09 a.m. EDT on July 2nd. At the moment of perigee, the moon's distance from Earth was 222,107 miles (357,448 kilometers).

This circumstance will result in a dramatically large range of high and low ocean tides during this Independence Day weekend. Any coastal storm at sea around this time will almost certainly aggravate coastal flooding problems. Such an extreme tide is known as a perigean spring tide, the word spring being derived from the German springen -- to "spring up," not a reference to the spring season. While this will be one of the "biggest" full moons of 2004 (the June full moon was slightly closer) the variation of the moon's size due to its distance is not readily apparent to observers viewing the moon directly. To those living on the shores near the Bay of Fundy in eastern Canada, however, the 10 to 20 foot (3 -6 meter) increase in the vertical tidal range makes it obvious when the moon lies near perigee, clear skies or cloudy. Copyright © 1999-2006 SPACE.com, Inc.

Singing the Blues: August Will Be a Blue Moon Month Singing the Blues: August Will Be a Blue Moon Month By Joe Rao, SPACE.com Skywatching Columnist | July 27, 2012 03:31pm ET MORE This image of the full moon was taken by Alamelu Sundaramoorthy from Portland, Ore. on July 3, 2012. Credit: Alamelu Sundaramoorthy The month of August brings us not one, but two full moons. The first will kick off the month on Wednesday (Aug.1), and will be followed by a second on Aug. 31. Some almanacs and calendars assert that when two full moons occur within a calendar month, the second full moon is called a " blue moon ." The full moon that night will likely look no different than any other full moon . But the moon can change color in certain conditions. After forest fires or volcanic eruptions, the moon can appear to take on a bluish or even lavender hue. Soot and ash particles, deposited high in the Earth's atmosphere, can sometimes make the moon appear bluish.

Smoke from widespread forest fire activity in western Canada created a blue moon across eastern North America in late September 1950. In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were reports of blue moons (and even blue suns) worldwide. [ Infographic: Blue Moons Explained ] Origin of the term The phrase "once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, though not truly rare. Yet, to have two full moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 2.66 years. And in the year 1999, it occurred twice in a span of just three months. For the longest time no one seemed to have a clue as to where the "blue moon rule" originated.

Many years ago in the pages of Natural History magazine , I speculated that the rule might have evolved out of the fact that the word "belewe" came from the Old English, meaning, "to betray." "Perhaps," I suggested, "the second full Moon is 'belewe' because it betrays the usual perception of one full moon per month." But as innovative as my explanation was, it turned out to be completely wrong. More mistakes It was not until that "double blue moon year" of 1999 that the origin of the calendrical term "blue moon" was at long last discovered. It was during the time frame from 1932 through 1957 that the Maine Farmers' Almanac suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, that the third full moon should be called a blue moon.

But thanks to a couple of misinterpretations of this cryptic definition, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 in a syndicated radio program, it now appears that the second full moon in a month is the one that's now popularly accepted as the definition of a blue moon. This time around, the moon will turn full on Aug. 31 at 9:58 a.m. Eastern Daylight Time (6:58 a.m. Pacific Standard Time), making it a blue moon. However, there is an exception: for those living in the Kamchatka region of the Russian Far East as well as in New Zealand, that same full moon occurs after midnight, on the calendar date of Sept. 1. So in these regions of world, this will not be the second of two full moons in August, but the first of two full moons in September. So, if (for example) you reside in Petropavlovsk-Kamchatsky or Christchurch, you'll have to wait until September 30 to declare that the moon is "officially" blue.

Blue Moon/New Moon While we've assigned the name blue moon to the second full moon of the month, it seems that we have no such name for the second new moon of the month. Nonetheless, these opposing phases seem to be connected with each other. For if two new moons occur within a specific month, then in most cases, four years later, two full moons will also occur in that very same month. As an example, there were two new moons in August 2008. Now, four years later, August 2012 will be graced with two full moons. The next time we will see two full moons in a single month comes in July 2015 (July 1 and 31). But if you still have a calendar leftover from last year, check the month of July. You'll find that there were two new moons on the 1st and the 30th. Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

August Will Be a Blue Moon Month - Seeker Jul 30, 2012 03:00 AM ET August Will Be a Blue Moon Month The month of August will be a blue moon month. Learn more about where the term blue moon came from and find out why August will be a blue moon month. Alamelu Sundaramoorthy This image of the full moon was taken by Alamelu Sundaramoorthy from Portland, Ore. on July 3, 2012. Alamelu Sundaramoorthy — August will bring not just one, but two full moons. — The first one will appear August 1 and the second will show on August 31. — When there are two full moons in one month, the second one is referred to as a blue moon. The month of August brings us not one, but two full moons. The first will kick off the month on Wednesday (Aug.1), and will be followed by a second on Aug. 31. Some almanacs and calendars assert that when two full moons occur within a calendar month, the second full moon is called a " blue moon ." The full moon that night will likely look no different than any other full moon .

But the moon can change color in certain conditions. PHOTOS: Supermoon: Readers' Photos After forest fires or volcanic eruptions, the moon can appear to take on a bluish or even lavender hue. Soot and ash particles, deposited high in the Earth's atmosphere, can sometimes make the moon appear bluish. Smoke from widespread forest fire activity in western Canada created a blue moon across eastern North America in late September 1950. In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were reports of blue moons (and even blue suns) worldwide. [ Infographic: Blue Moons Explained ] Origin of the term The phrase "once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, though not truly rare. Yet, to have two full moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 2.66 years. And in the year 1999, it occurred twice in a span of just three months. For the longest time no one seemed to have a clue as to where the "blue moon rule" originated.

Many years ago in the pages of Natural History magazine , I speculated that the rule might have evolved out of the fact that the word "belewe" came from the Old English, meaning, "to betray." "Perhaps," I suggested, "the second full Moon is 'belewe' because it betrays the usual perception of one full moon per month." But as innovative as my explanation was, it turned out to be completely wrong. More mistakes It was not until that "double blue moon year" of 1999 that the origin of the calendrical term "blue moon" was at long last discovered. It was during the time frame from 1932 through 1957 that the Maine Farmers' Almanac suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, that the third full moon should be called a blue moon.

NEWS: Evidence of Water Found in Moon Crater But thanks to a couple of misinterpretations of this cryptic definition, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 in a syndicated radio program, it now appears that the second full moon in a month is the one that's now popularly accepted as the definition of a blue moon. This time around, the moon will turn full on Aug. 31 at 9:58 a.m. Eastern Daylight Time (6:58 a.m. Pacific Standard Time), making it a blue moon. However, there is an exception: for those living in the Kamchatka region of the Russian Far East as well as in New Zealand, that same full moon occurs after midnight, on the calendar date of Sept. 1. So in these regions of world, this will not be the second of two full moons in August, but the first of two full moons in September. So, if (for example) you reside in Petropavlovsk-Kamchatsky or Christchurch, you'll have to wait until September 30 to declare that the moon is "officially" blue.

Blue Moon/New Moon While we've assigned the name blue moon to the second full moon of the month, it seems that we have no such name for the second new moon of the month. Nonetheless, these opposing phases seem to be connected with each other. For if two new moons occur within a specific month, then in most cases, four years later, two full moons will also occur in that very same month. As an example, there were two new moons in August 2008. Now, four years later, August 2012 will be graced with two full moons. The next time we will see two full moons in a single month comes in July 2015 (July 1 and 31). But if you still have a calendar leftover from last year, check the month of July. You'll find that there were two new moons on the 1st and the 30th. Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for the New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York. Copyright 2012 SPACE.com , a TechMediaNetwork company.

All rights reserved. This material may not be published, broadcast, rewritten or redistributed. MUST WATCH Blue Moon to Occur New Year's Eve Blue Moon to Occur New Year's Eve By Joe Rao, SPACE.com Skywatching Columnist | December 30, 2009 08:51am ET MORE [Find out when is the next blue moon .] New Year's Eve brings us the second of two full moons for North Americans this month. Some almanacs and calendars assert that when two full moons occur within a calendar month, that the second full moon is called the "blue moon." The term has a very interesting history, riddled with misconceptions and errors. More on that lower down. First, what will (and won't) happen: The full moon that night will likely look no different than any other full moon (other than the fact that a partial eclipse will occur across most of Europe, Africa, and Asia). But the moon can change color in certain conditions. After forest fires or volcanic eruptions, the moon can appear to take on a bluish or even lavender hue. Soot and ash particles, deposited high in the Earth's atmosphere, can sometimes make the moon appear bluish.

In one example, smoke from widespread forest fire activity in western Canada created a blue moon across eastern North America in late September 1950. In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were reports of blue moons (and even blue suns) worldwide.? Origin of the term The phrase "Once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, though not truly rare. Yet, to have two full moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 32 months. And in the year 1999, it occurred twice in a span of just three months! For the longest time no one seemed to have a clue as to where the "blue moon Rule" originated.

Many years ago in the pages of Natural History magazine, I speculated that the rule might have evolved out of the fact that the word "belewe" came from the Old English, meaning, "to betray." "Perhaps," I suggested, "the second full moon is 'belewe' because it betrays the usual perception of one full moon per month." But as innovative as my explanation was, it turned out to be completely wrong. More mistakes It was not until the year 1999 that the origin of the calendrical term "blue moon" was at long last discovered.

It was during the time frame from 1932 through 1957 that the Maine Farmers' Almanac suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, that the third full moon should be called a "blue moon." But thanks to a couple of misinterpretations of this arcane rule, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 in a syndicated radio program, the second full moon in a month is the one that's now popularly accepted as the definition of a "blue moon."?? This time around, the moon will turn full on Dec. 31 at 2:14 p.m. Eastern Standard Time (11:14 a.m. Pacific Daylight Time). But for those living in central and eastern Asia, as well as Australia and New Zealand, that same full moon occurs after midnight, on the calendar date of Jan. 1, 2010.

So in these regions of world, this will not be second of two full moons in December 2009, but the first of two full moons in January 2010. So, if (for example) you live Perth or Tokyo, you'll have to wait until January 30 to declare that the moon is "officially" blue. Eclipse for some This week's full moon will also undergo a partial eclipse. The moon will dip slightly into the Earth's umbra ? the dark, hard-edged shadow ? which will show black or dark brown on the moon's southern limb for just over an hour; this will be a pre-midnight New Year's Eve show for Europe, Africa and western Asia, while for central and eastern Asia, Indonesia and western and central Australia this will happen in the post-midnight hours of the first day of 2010. Maximum eclipse will come at 19:23 UT, when just 8.2-percent of the moon's diameter is within the umbra. Unfortunately, most of North America (except for northern Alaska and northernmost Canada) is out of the zone of visibility for this eclipse.

The last time a blue moon coincided with New Year's Eve was in 1990. The next opportunity will come in 2028. Why isn't a "blue moon" blue? - | WBTV Charlotte Why isn't a "blue moon" blue? - | WBTV Charlotte Member Center: Marketplace Why isn't a "blue moon" blue? CHARLOTTE, NC (WBTV) - In short, it can be, but a "blue moon" has nothing to do with the color of the moon. Roughly once every 2.7 years, two full moon will occur within the same calendar month. This is referred to as a blue moon. According to a NASA article , the expression originally had nothing to do with astronomy. It was simply an expression that meant rare or ridiculous. The modern definition came about in the 1940s when Sky & Telescope magazine published an article written by James Hugh Pruett entitled "Once in a Blue Moon." Pruett cited the 1937 Maine Farmer's Almanac, which gave a convoluted definition of the term.

He then stated that the "second [full moon] in a month, so I interpret it, is called the Blue Moon." While not technically correct, the meaning stuck, and it's been the modern definition ever since. It takes just over 29.5 Earth days for the moon to completely move through its entire cycle. It's known as the synodic period, and it's the reason that a blue moon in February will never occur, even in a leap year. There simply aren't enough days. Even though a blue moon is typically the same gray and white color we usually see in the night sky, on rare occasions it CAN be blue. Blue "blue moons" are usually blue when large volcanic eruptions send huge amounts of ash and dust into the atmosphere. Several volcanic eruptions have resulted in color changes in both the moon and the sun. When some volcanoes erupt, very small particles of about 1 micron in diameter are sent into the atmosphere. Particles this size are about the same as the wavelength of red light, in effect filtering the red color out and allowing the blue to pass through. We saw it with Krakatoa's eruption in 1883 and in 1980 when Mt. St. Helens exploded.

Forest fires have also been known to cause blue moons. The next blue moon occurs on July 31, 2015. We get two blue moons in 2018 when they fall within January and March. For the technical meaning of a blue moon, click here . Singing the blues: August will be a blue moon month - Technology & science - Space - Space.com | NBC News Advertise Singing the blues: August will be a blue moon month When two full moons occur within a calendar month, the second full moon is called a 'blue moon' Below: Advertise Alamelu Sundaramoorthy This image of the full moon was taken by Alamelu Sundaramoorthy from Portland, Ore. on July 3, 2012. By Joe Rao + - The month of August brings us not one, but two full moons. The first will kick off the month on Wednesday (Aug.1), and will be followed by a second on Aug. 31. Some almanacs and calendars assert that when two full moons occur within a calendar month, the second full moon is called a " blue moon ." The full moon that night will likely look no different than any other full moon .

But the moon can change color in certain conditions. After forest fires or volcanic eruptions, the moon can appear to take on a bluish or even lavender hue. Soot and ash particles, deposited high in the Earth's atmosphere, can sometimes make the moon appear bluish. Smoke from widespread forest fire activity in western Canada created a blue moon across eastern North America in late September 1950. In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were reports of blue moons (and even blue suns) worldwide. [ Infographic: Blue Moons Explained ] Origin of the term The phrase "once in a blue moon" was first noted in 1824 and refers to occurrences that are uncommon, though not truly rare. Yet, to have two full moons in the same month is not as uncommon as one might think. In fact, it occurs, on average, about every 2.66 years. And in the year 1999, it occurred twice in a span of just three months.

Space news from NBCNews.com Watch a 'ring of fire' solar eclipse online For the longest time no one seemed to have a clue as to where the "blue moon rule" originated. Many years ago in the pages of Natural History magazine , I speculated that the rule might have evolved out of the fact that the word "belewe" came from the Old English, meaning, "to betray." "Perhaps," I suggested, "the second full Moon is 'belewe' because it betrays the usual perception of one full moon per month." But as innovative as my explanation was, it turned out to be completely wrong. Advertise More mistakes It was not until that "double blue moon year" of 1999 that the origin of the calendrical term "blue moon" was at long last discovered. It was during the time frame from 1932 through 1957 that the Maine Farmers' Almanac suggested that if one of the four seasons (winter, spring, summer or fall) contained four full moons instead of the usual three, that the third full moon should be called a blue moon.

But thanks to a couple of misinterpretations of this cryptic definition, first by a writer in a 1946 issue of Sky & Telescope magazine, and much later, in 1980 in a syndicated radio program, it now appears that the second full moon in a month is the one that's now popularly accepted as the definition of a blue moon. This time around, the moon will turn full on Aug. 31 at 9:58 a.m. Eastern Daylight Time (6:58 a.m. Pacific Standard Time), making it a blue moon. However, there is an exception: for those living in the Kamchatka region of the Russian Far East as well as in New Zealand, that same full moon occurs after midnight, on the calendar date of Sept. 1. So in these regions of world, this will not be the second of two full moons in August, but the first of two full moons in September. So, if (for example) you reside in Petropavlovsk-Kamchatsky or Christchurch, you'll have to wait until September 30 to declare that the moon is "officially" blue.

Blue moon/New moon While we've assigned the name blue moon to the second full moon of the month, it seems that we have no such name for the second new moon of the month. Nonetheless, these opposing phases seem to be connected with each other. For if two new moons occur within a specific month, then in most cases, four years later, two full moons will also occur in that very same month. As an example, there were two new moons in August 2008. Now, four years later, August 2012 will be graced with two full moons. The next time we will see two full moons in a single month comes in July 2015 (July 1 and 31). But if you still have a calendar leftover from last year, check the month of July. You'll find that there were two new moons on the 1st and the 30th. Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York. © 2013 Space.com. All rights reserved.

More from Space.com . Photos: Month in Space: January 2014 Related slideshows Southern stargazing Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Share Back to slideshow navigation Advertise A balloon's view Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June.

The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Share Back to slideshow navigation Spacemen at work Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Share Back to slideshow navigation Related slideshow Our fragile Earth Special delivery The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Share Back to slideshow navigation Accidental art A piece of art? A time-lapse photo? A flickering light show?

At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Share Back to slideshow navigation Related video Watch Virgin Galactic's Supersonic Test Flight Supersonic test flight A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

• More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Share Back to slideshow navigation Red lagoon The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Share Back to slideshow navigation Related slideshow Thousands evacuate as Colby Fire burns Fire on the mountain This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Share Back to slideshow navigation Where stars are born An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away.

This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Share Back to slideshow navigation Cygnus takes flight Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Share Back to slideshow navigation A long, long time ago... This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies.

The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Share Back to slideshow navigation Advertise Frosty halo Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill. This image contains graphic content that some viewers may find disturbing. Click to view the image, or use the buttons above to navigate away. This image contains graphic content that some viewers may find disturbing. Click to view the image, or use the buttons above to navigate away. This image contains graphic content that some viewers may find disturbing. Click to view the image, or use the buttons above to navigate away.

Question: The second full moon occurring within a calendar month is known as a ‘what’ Moon?
Answer: Blue Moon