VANCOUVER — Stargazers across Canada were in for a two-for-one treat Sunday night with the rare confluence of a total lunar eclipse with a so-called supermoon.
A supermoon occurs when a full or new moon makes its closest approach to the Earth and appears slightly larger and brighter than normal.
Luke Yates was able to enjoy the unique event from the comfort and vantage of his apartment on Canada’s East Coast, which also happened to be located in the tallest building in Halifax.
“I’m pretty excited. I love this sort of thing,” said the British native, who was living in Nova Scotia for school. “The reflection on the harbour in Halifax is gorgeous.”
He watched the Earth’s shadow begin to creep across the moon’s surface, describing the experience as awe-inspiring.
His earlier attempts to photograph the lunar phenomenon were unsuccessful, he said: “It’s too bright. Unless you’ve got a really top-end camera it comes out like the sun.”
Meanwhile, Jeff Smith chose to take his family to the top of the Centennial Park ski hill in Etobicoke, Ont., to absorb the view, albeit under slightly cloudier circumstances.
While the weather made for less-than-perfect picture-taking opportunities, Smith was more philosophical when reflecting on the degree of excitement that had built up through social media for the relatively rare celestial occurrence.
“It’s one of those things that sort of brings people down to Earth, ” he mused. “It’s a little humbling if you get out and appreciate it for what it is.”
The weather was even less co-operative in Calgary, where cloud cover prevented many from taking in the sight.
The city’s social media-savvy mayor, Naheed Nenshi, took to Twitter to comment dryly on the overcast skies, prompting invitations to join other moongazers elsewhere in the country.
No such viewing troubles were to be had in Manitoba, where Todd Scott watched the show from Grand Marais, about 100 kilometres north of Winnipeg.
“It’s perfectly clear. The light has just been fantastic. There are waves coming off the lake you can hear on the marsh. The birds are chirping away,” he said.
“You can see the shadow slowly coming over the moon, almost like the edge of a finger on a photograph.”
As the moon was eclipsed by the Earth’s shadow on Sunday it also turned a reddish colour, an eerie wonder known as a Blood Moon.
The timing of the eclipse was good for most parts of Canada, but those on the West Coast missed the initial stages because the moon was lower in the sky.
The next total eclipse won’t happen until 2018, and the next total eclipse of a supermoon won’t happen until 2033.
September 2015 lunar eclipse
A total lunar eclipse took place between September 27 and 28, 2015. It was seen Sunday evening, September 27, in the Americas; while in Europe, Africa, and the Middle East, it was seen in the early hours of Monday morning, September 28. It was the latter of two total lunar eclipses in 2015, and the final in a tetrad (four total lunar eclipses in series). Other eclipses in the tetrad are those of April 15, 2014, October 8, 2014, and April 4, 2015.
The Moon appeared larger than normal because the Moon was just 59 minutes past its closest approach to Earth in 2015 at mid-eclipse, sometimes called a supermoon. The Moon’s apparent diameter was larger than 34′ viewed straight overhead, just off the coast of northeast Brazil.
This eclipsed moon appeared 12.9% larger in diameter than the April 2015 lunar eclipse, measured as 29.66′ and 33.47′ in diameter from earth’s center, as compared in these simulated images.
A supermoon is the coincidence of a full moon or a new moon with the closest approach the Moon makes to the Earth on its elliptical orbit, resulting in the largest apparent size of the lunar disk as seen from Earth.
A lunar eclipse occurs when the Moon passes within Earth’s umbra (shadow). As the eclipse begins, Earth’s shadow first darkens the Moon slightly. Then, the shadow begins to “cover” part of the Moon, turning it a dark red-brown color (typically – the color can vary based on atmospheric conditions). The Moon appears to be reddish because of Rayleigh scattering (the same effect that causes sunsets to appear reddish) and the refraction of that light by Earth’s atmosphere into its umbra.
The following simulation shows the approximate appearance of the Moon passing through Earth’s shadow. The Moon’s brightness is exaggerated within the umbral shadow. The northern portion of the Moon was closest to the center of the shadow, making it darkest, and most red in appearance.
What is a supermoon?
What’s a supermoon? It’s a new or full moon closely coinciding with perigee – the moon’s closest point to Earth in its monthly orbit. An astrologer, Richard Nolle, coined the term supermoon over 30 years ago, but now many in astronomy use it as well. Are supermoons hype? In our opinion … gosh, no, just modern folklore. They’ve entered the popular culture (check out Sophie Hunger’s music video in this post, for example). And they can cause real physical effects, such as larger-than-usual tides. According to the definition of supermoon coined by Nolle, the year 2015 has a total of six supermoons. The new supermoons of January, February and March have passed. The full supermoon of August has also passed, and now we’re coming up on the year’s closest supermoon, on the night of September 27-28, which will also be called a Blood Moon and which will also undergo a total lunar eclipse. Finally, there will be a third full supermoon in October. Follow the links below to learn about the supermoons of 2015.
What is a supermoon? We confess: before a few years ago, we in astronomy had never heard that term. To the best of our knowledge, astrologer Richard Nolle coined the term supermoonover 30 years ago. The term has only recently come into popular usage. Nolle has defined a supermoon as:
… a new or full moon which occurs with the moon at or near (within 90% of) its closest approach to Earth in a given orbit.
That’s a pretty generous definition, which is why there areso many supermoons. By this definition, according to Nolle:
There are 4-6 supermoons a year on average.
Some astronomers have complained about the name … but we like it! And it’s entered the popular culture. for example, Supermoon is the title track of Sophie Hunger’s new album, due for release in May, 2015. It’s a nice song!
What is a Blood Moon?
However, the new moon supermoon on February 18 only lies about 200 kilometers farther away than the September 28 full moon supermoon. At a distance of 357,098 kilometers or 221,890 miles, the new moon of February 18 features the second-closest supermoon of 2015.
Want more detail? Okay. In 2015, the moon comes closest to Earth on September 28 (356,877 kilometers), and swings farthest away some two weeks before, on September 14 (406,464 kilometers). That’s a difference of 49,587 kilometers (406,464 – 356,877 = 49,587). Ninety percent of this 49,587-figure equals 44,628.3 kilometers (0.9 x 49,587 = 44,628.3). Presumably, any new or full moon coming closer than 361,863.1 kilometers (406,464 – 44,628.3 = 361,835.7) would be “at or near (within 90% of) its closest approach to Earth.”
Spring tides will accompany the supermoons. Will the tides be larger than usual at the January, February and March 2015 new moons and the August, September and October 2015 full moons? Yes, all full moons (and new moons) combine with the sun to create larger-than-usual tides, but closer-than-average full moons (or closer-than-average new moons) elevate the tides even more.
Each month, on the day of the new moon, the Earth, moon and sun are aligned, with the moon in between. This line-up creates wide-ranging tides, known as spring tides. High spring tides climb up especially high, and on the same day low tides plunge especially low.
The closest new moon of the year on February 18 and the year’s closest full moon on September 28 are bound to accentuate the spring tide all the more, giving rise to what’s called a perigean spring tide. If you live along an ocean coastline, watch for high tides caused by the September 27-28 perigean full moon.
Will these high tides cause flooding? Probably not, unless a strong weather system accompanies the perigean spring tide. Still, keep an eye on the weather, because storms do have a large potential to accentuate perigean spring tides.
Dates of closest full supermoons in past and future years. More often than not, the one day of the year that the full moon and perigee align also brings about the year’s closest perigee (also called proxigee). Because the moon has recurring cycles, we can count on the full moon and perigee to come in concert in periods of about one year, one month and 18 days.
Therefore, the full moon and perigee realign in periods of about one year and 48 days. So we can figure the dates of the closest full moons in recent and future years as:
March 19, 2011
May 6, 2012
June 23, 2013
August 10, 2014
September 28, 2015
November 14, 2016
January 2, 2018.
There won’t be a perigee full moon in 2017 because the full moon and perigee won’t realign again (after November 14, 2016) until January 2, 2018.
Looking further into the future, the perigee full moon will come closer than 356,500 kilometers for the first time in the 21st century (2001-2100) on November 25, 2034 (356,446 km). The closest full moon of the 21st century will fall on December 6, 2052 (356,425 km).
By the way, some astronomers will call all the full moons listed above proxigee full moons.
But, like many of you, we’ll have fun just calling ’em supermoons.
What is a Black Moon?
We had never heard the term Black Moon until early 2014. It doesn’t come from astronomy, or skylore, either. Instead, according to David Harper, the term comes from Wiccan culture. It’s the name for the second of two new moons in one calendar month. January 2014, for example, had two new moon supermoons, the second of which was not only a supermoon, but a Black Moon. Does a Black Moon have to be a supermoon in order to be called Black? No. You can read more about Black Moons here.
The next Black moon by the above definition will occur on October 30, 2016. Sten Odenwald at astronomycafe.net lists some other names for the second new moon in a month: Spinner Moon, Finder’s Moon, Secret Moon.
However, we’ve also come across another definition for Black Moon: the third of four new moons in one season. This last happened with the new moon supermoon of February 18, 2015, because this particular new moon was the third of four new moons to take place between the December 2014 solstice and the March 2015 equinox. The next Black Moon by this definition will occur on August 21, 2017, to feature a Black Moon total solar eclipse in the United States.
Bottom line: The term supermoon doesn’t come from astronomy. It comes from astrology, and the definition is pretty generous so that there are 4 to 6 supermoons each year. This post explains what a supermoon is, how many will occur in 2015, which moon is the most “super” of all the 2015 supermoons, and gives a list of upcoming full supermoons for the years ahead.