The full moon reappears in March, on the 31st at 08:37 EDT, a second time. Whenever two full moons occur in one month, which happens approximately every 2.66 years, the second (by definition) is baptized the "Blue Moon".
And yet this is the second Blue Moon since the beginning of the year – the second time in three months that two full moons have taken place in a calendar month. What is the reason for this anomaly? The time it takes the moon to travel from one full moon to the next (on average 29.53 days) is called the "synodic" month. February is the only calendar month that is shorter than a synodic month, and this year he did not have a full moon. To make up for this deficiency, March ended with an additional full moon. There were also two full moons in January, giving us two Blue Moons in just 60 days, even though the Blue Moon is the last one on Saturday.
The mainstream media has the January Blue Moon (on the 31
Set date for Easter
Also our March Blue Moon will bring something unusual: it will be a "Paschal" moon.
Spring began on March 20th, and eleven days later the moon becomes full. This is also the first full moon of spring and as such it is called Easter Moon. The first Sunday after the Paschal Moon is usually called Easter Sunday, as it will be the next day, April 1.
But the ecclesiastical date adopted for the full moon, can not coincide exactly with the astronomical. Thus, Easter is determined in practice from other formulas involving Epas and Golden Numbers. These rules also state that the vernal equinox will be set on March 21st, although the equinox of 2008 to 2101 will be held by the Vatican City no later than March 20th. In 2038, Easter will be watched as late as possible. on the 25th of April. The earliest date for Easter is March 22, which will not happen until 2285.
Blue Moon Curiosities
A Paschal Moon, which is also a Blue Moon, can only occur in March.
The last time we had a blue Paschal Moon in 1999. In that year, the full moon fell on a Wednesday in the second of March, so that Easter Sunday on the 4th April fell. Next time we will have a Paschal Blue Moon will be 2037.
If you're wondering when Easter Sunday last fell on April 1 – that was in 1956.
But when did we have a similar case like this year, a Blue Paschal Moon on March 31, the next day on Easter Sunday?
In the year 1714, the full moon was Universal Time at 3:17 am on March 31, followed by the next day until Easter Sunday. But that was only true for Europe and the eastern hemisphere. For the western hemisphere, the full moon was the day before (on March 30).
For North America we have to go back to the year 1646 to have a case repeating this month: a blue Easter moon on Saturday, March 31, followed by Easter Sunday the next day. Incidentally, we know that the original colonies still followed the Julian calendar and not the current Gregorian calendar, first introduced in 1582 by Pope Gregory. England and the American colonies did not change until 1752, throwing a wrench into this special Easter calculation, as it would throw everything away for 10 days.
So, that would suggest that the upcoming circumstance of a Blue Easter Moon, followed immediately by Easter Sunday on April 1st, is truly unique!
And finally, our next blue moon will coincide again with a remarkable day: October 31 (Halloween) in 2020.
Why do I suddenly imagine a blue-colored pumpkin lantern?
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Joe Rao is a lecturer and guest lecturer at the New York Hayden Planetarium. He writes about astronomy for the Natural History Magazine, the Farmer's Almanac and other publications, and he is also a cameraman for Fios1 News in Rye Brook, New York. Follow us on @ Spacedotcom Facebook or Google+. Originally published on Space.com.