when is the next total lunar eclipse? Archives

Hey, how ’bout that annular eclipse last week? Some great images flooded in to Universe Today, as the final solar eclipse for 2016 graced the African continent. This not only marked the start of the second and final eclipse season for 2016, but it also set us up for the final eclipse of the year next week.

The path of next week's penumbral eclipse through the Earth's shadow. Adapted from NASA/GSFC/F. Espenak. — The path of next week’s penumbral eclipse through the Earth’s shadow. Adapted from NASA/GSFC/F. Espenak.

We’re talking about the penumbral lunar eclipse coming up next week on September 16^th, 2016. this sort of eclipse occurs when the Moon just misses the dark inner core (umbra) of the Earth’s shadow, and instead, drifts through its relatively bright outer cone, known as the penumbra. Though not the grandest show as eclipses go, astute observers should notice a subtle light tea-colored shading of the Full Moon, and perhaps the ragged dark edge of the umbra on the northwestern limb of the Moon as it brushes by around mid-eclipse.

The visibility map for next week's eclipse. Image credit: NASA/GSFC/Fred Espenak. — The visibility map for next week’s eclipse. Image credit: NASA/GSFC/Fred Espenak.

The entirety of the eclipse will be visible from the region surrounding the Indian Ocean on the evening of Friday, September 6^th. Viewers in Australia, New Zealand and Japan will see the eclipse transpire at moonset, and the eclipse will get underway at moonrise for observers in western Africa and Europe.

The eclipse runs from first contact at 16:55 Universal Time (UT) to 20:54 UT when the Moon quits the Earth’s shadow almost four hours later. Mid-eclipse occurs at 18:55 UT, with the Moon 91% immersed in the Earth’s outer shadow.

Tales of the Saros

This particular eclipse is member 9 of the 71 lunar eclipses in saros series 147. This saros began on July 2^nd 1890 and runs through to the final eclipse in the cycle on May 1^st 2990. It will produce its very first partial eclipse next time around on September 28^th 2034, and its first total lunar eclipse on June 6^th, 2449.

Why penumbrals? Aren’t they the ultimate non-event when it comes to eclipses? Like with much of observational astronomy, a penumbral lunar eclipse pushes our skills as a visual athlete to the limit. Check out the waxing gibbous Moon the night before the eclipse, then the Moon the night of the event. If you didn’t know any better, could you tell the difference from one night to the next? Often, the camera can see what the eye can’t. Photographing the Moon before, during and after a penumbral eclipse will often bring out the subtle shading on post-comparison. You’ll want to photograph the Moon when its high in the sky and free of atmospheric distortion low to the horizon, which tends to discolor the Moon. Such a high-flying Moon during mid-eclipse favors the Indian Subcontinent this time around. We’ve yet to see a good convincing time-lapse documenting a penumbral eclipse, though such a feat is certainly possible.

See anything... shady going on? Here's the penumbral lunar eclipse from this past March. Image credit and copyright: Neeraj Ladia — See anything… shady going on? Here’s the penumbral lunar eclipse from this past March. Image credit and copyright: Neeraj Ladia

When is an eclipse… not an eclipse? By some accounts, the Moon underwent a very shallow penumbral one cycle ago on August 18^th, 2016, though the brush past the shadow was so slight that many lists, including the NASA’s GSFC eclipse page omitted it. Three eclipses (a lunar partial and a penumbral, or two penumbrals and one solar) can occur in one eclipse season, if the nodes of the Moon’s orbit where it intersects the ecliptic fall just right. This last occurred in 2013, and will happen again in 2020.

And when there’s a lunar eclipse, there’s also a Full Moon. The September Full Moon is the Harvest Moon, providing a few extra hours of illumination to get the crops in. This year, the Harvest Moon falls just six days from the equinox on September 22^nd, marking the start of astronomical Fall in the northern hemisphere and Spring in the southern. The relative ecliptic angle also ensures that moonrise only slides back by a slight amount each evening for observers in mid-northern latitudes around the Harvest Moon.

Can’t wait til the next eclipse? Well, 2017 has four of ’em: an annular on February 26th favoring South America, two lunars (another penumbral on February 11^th and a partial on August 7^th) and oh yeah, there’s a total solar eclipse crossing the United States on August 21st. And the next total lunar eclipse? The dry spell is broken on January 31^st, 2018, when a total lunar eclipse favoring the Pacific Rim occurs. Yeah, we got spoiled with four back-to-back lunar eclipses during the Blood Moon tetrad of 2014-2015…

Read Dave Dickinson’s eclipse-fueled sci-fi tales Exeligmos, Shadowfall, The Syzygy Gambit and Peak Season.

By now, you may have already heard the latest tale of gloom and doom surrounding the upcoming series of lunar eclipses.

This latest “End of the World of the Week” comes to us in what’s being termed as a “Blood Moon,” and it’s an internet meme that’s elicited enough questions from friends, family and random people on Twitter that it merits addressing from an astronomical perspective.

Like the hysteria surrounding the supposed Mayan prophecy back in 2012 and Comet ISON last year, the purveyors of Blood Moon lunacy offer a pretty mixed and often contradictory bag when it comes down to actually what will occur.

But just like during the Mayan apocalypse nonsense, you didn’t have to tally up just how many Piktuns are in a Baktun to smell a rat. December 21^st 2012 came and went, the galactic core roughly aligned with the solstice — just like it does every year — and the end of the world types slithered back into their holes to look for something else produce more dubious YouTube videos about.

Here’s the gist of what’s got some folks wound up about the upcoming cycle of eclipses. The April 15^th total lunar eclipse is the first in series of four total eclipses spanning back-to-back years, known as a tetrad. There are eight tetrads in the 21^st century: if you observed the set total lunar eclipses back in 2003 and 2004, you saw the first tetrad of the 21^st century.

The eclipses in this particular tetrad, however, coincide with the Full Moon marking Passover on April 15^th and April 4^th and the Jewish observance of Sukkot on October 8^th and September 28^th. Many then go on to cite the cryptic biblical verse from Revelation 6:12, which states;

“I watched as he opened the sixth seal. There was a great earthquake. The Sun turned black like sackcloth made of goat hair. The whole Moon turned blood red.”

Whoa, some scary allegory, indeed… but does this mean the end of the world is nigh?

I wouldn’t charge that credit card through the roof just yet.

First off, looking at the eclipse tetrads for the 21^st century, we see that they’re not really all that rare:

21^st century eclipse tetrads:

Eclipse #1	Eclipse #2	Eclipse #3	Eclipse #4
May 16^th, 2003	November 9^th, 2003	May 4^th , 2004	October 28^th, 2004
April 15^th, 2014*+	October 8^th, 2014	April 4^th, 2015*+	September 28^th, 2015
April 25^th, 2032	October 18^th, 2032	April 14^th, 2033*+	October 8^th, 2033
March 25^th, 2043*	September 19^th, 2043	March 13^th, 2044	September 7^th, 2044
May 6^th, 2050	October 30^th, 2050	April 26^th, 2051	October 19^th, 2051
April 4^th, 2061*+	September 29^th, 2061	March 25^th, 2062*	September 18^th, 2062
March 4^th, 2072	August 28^th, 2072	February 22^nd, 2073	August 17^th, 2073
March 15^th, 2090	September 8^th, 2090	March 5^th, 2091	August 29^th, 2091
*Paschal Full Moon
+Eclipse coincides with Passover

Furthermore, Passover is always marked by a Full Moon, and a lunar eclipse always coincides with a Full Moon by definition, meaning it cannot occur at any other phase. The Jewish calendar is a luni-solar based calendar that attempts to mark the passage of astronomical time via the apparent course that the Sun and the Moon tracks through the sky. The Muslim calendar is an example of a strictly lunar calendar, and our western Gregorian calendar is an example of a straight up solar one. The Full Moon marking Passover often, though not always, coincides with the Paschal Moon heralding Easter. And for that matter, Passover actually starts at sunset the evening prior in 2014 on April 14^th. Easter is reckoned as the Sunday after the Full Moon falling after March 21^st which is the date the Catholic Church fixes as the vernal equinox, though in this current decade, it falls on March 20^th. Easter can therefore fall anywhere from March 22^nd to April 25^th, and in 2014 falls on the late-ish side, on April 20^th.

To achieve synchrony, the Jewish calendar must add what’s known as embolismic or intercalculary months (a second month of Adar) every few years, which in fact it did just last month. Eclipses happen, and sometimes they occur on Passover. It’s rare that they pop up on tetrad cycles, yes, but it’s at best a mathematical curiosity that is a result of our attempt to keep our various calendrical systems in sync with the heavens. It’s interesting to check out the tally of total eclipses versus tetrads over a two millennium span:

Century	Number of Total Lunar Eclipses	Number of Tetrads	Century	Number of Total Lunar Eclipses	Number of Tetrads
11^th	62	0	21^st	85	8
12^th	59	0	22^nd	69	4
13^th	60	0	23^rd	61	0
14^th	77	6	24^th	60	0
15^th	83	4	25^th	69	4
16^th	77	6	26^th	87	8
17^th	61	0	27^th	79	7
18^th	60	0	28^th	64	0
19^th	62	0	29^th	57	0
20^th	81	5	30^th	63	1

Note that over a five millennium span from 1999 BC to 3000 AD, the max number of eclipse tetrads that any century can have is 8, which occurs this century and last happened in the 9^th century AD.

Of course, the visual appearance of a “Blood of the Moon” that’s possibly alluded to in Revelation is a real phenomena that you can see next week from North and South America as the Moon enters into the dark umbra or core of the shadow of the Earth. But this occurs during every total lunar eclipse, and the redness of the Moon is simply due to the scattering of sunlight through the Earth’s atmosphere. Incidentally, this redness can vary considerably due to the amount of dust, ash, and particulate aerosols aloft in the Earth’s atmosphere, resulting in anything from a bright cherry red eclipse during totality to an eclipsed Moon almost disappearing from view altogether… but it’s well understood by science and not at all supernatural.

The changing colors of a lunar eclipse: a mosaic of four eclipses. Photos by author.

Curiously, the Revelation passage could be read to mean a total solar eclipse as well, though both can never happen on the same day. Lunar and solar eclipses occur in pairs two weeks apart at Full and New Moon phases when the nodes of the Moon’s ecliptic crossing comes into alignment with the Sun — known as a syzygy, an ultimate triple word score in Scrabble, by the way — and this eclipse season sees a non-central annular eclipse following the April 15^th eclipse on April 29^th.

And yes, earthquakes, wars, disease, relationship breakups and lost car keys are on tap to occur in 2014 and 2015… just like during any other year. Lunar eclipses marked the fall of Constantinople in 1453 and the World Series victory of the Red Sox in 2004, but they’re far from rare. We humans love to see patterns, and sometimes this habit works against us, making us see them where none exists. This is simply a case of the gambler’s fallacy, counting the hits at the cost of the misses. We could just as easily make a case that the upcoming eclipse tetrad of April 15th, October 8^th, April 4^th and September 28th marks US Tax Day, Croatian Independence Day, The Feast of Benedict of the Moor & — Michael Scott take note — International World Rabies Day… perhaps the final 2015 eclipse should be known as a “Rabies Moon?”

So, what’s the harm in believing in a little gloom and doom? The harm in believing the world ends tomorrow comes when we fail to plan for still being here the day after. The harm comes when something like the Heavens Gate mass suicide goes down. We are indeed linked to the universe, but not in the mundane and trivial way that astrologers and doomsdayers would have you believe. Science shows us where we came from and where we might be headed. We’ve already fielded queries from folks asking if it’s safe (!) to stare at the Blood Moon during the eclipse, and the answer is yes… don’t give in to superstition and miss out on this spectacular show of nature because of some internet nonsense.

The upcoming lunar eclipse next week won’t mean the end of the world for anyone, except, perhaps, NASA’s LADEE spacecraft… be sure not to miss it!

Tag: when is the next total lunar eclipse?

An Impalpable Penumbral Eclipse

The Science Behind the “Blood Moon Tetrad” and Why Lunar Eclipses Don’t Mean the End of the World