Shades of Glory

My whirlwind tour to the North Pole and back for 175 seconds of totality

Flight from Germany en route to the North Pole intercepted the Moon’s shadow at 9:41:33 a.m. Greenwich Mean Time. During the brief “totality run” the aircraft flew northeastward, broadside to the Sun, to provide a view of the eclipse from the passenger windows on the right side (it being morning, the Sun was in the east).

Illustration by Ian Worpole (www.IanWorpole.com)

Background photo: View through aircraft window of the August 1, 2008, solar eclipse shows the “diamond ring” effect created by the irregular edge of the Moon, just before the Moon completely covers the solar disk.

Photos by Joe Rao

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October 2008

As regular readers of my “Skylog” column are aware, a total solar eclipse was predicted for August 1, 2008, one whose track would stretch from northern Canada across the Arctic Circle and into Siberia and China. Although I had traveled to witness nine previous eclipses, I figured I would have to forego this one—hard to reach from my home base near New York City. Even a trip to Novosibirsk—a readily accessible major city in Siberia, directly in the path of the eclipse—didn’t seem worth the investment of time and money. The likelihood of clear skies there was little better than fifty-fifty, given the usual weather patterns at that time of year. But then, in late June, I was presented with an opportunity to observe the eclipse from a most unique vantage point.

Once or twice a year, a German tour company called Deutsche Polarflug runs a twelve-hour sightseeing flight to the North Pole and back. Their flight path scheduled for August 1 promised an unusual bonus: en route to the Pole, it would intercept the total eclipse, and the aircraft would be filled with scientists and inveterate eclipse chasers. When I was invited aboard to cover this event for Natural History, I readily accepted!

Passengers take in views prior to the eclipse.

Photo by Joe Rao

Total solar eclipses are a happy accident of nature. The Sun’s 864,000-mile diameter is fully 400 times larger than that of our puny Moon, which is 2,160 miles. But the Moon also happens to be about 400 times closer to the Earth than the Sun (the ratio varies a bit, as both orbits are elliptical), and as a result, when the orbital planes intersect and the distances align favorably, the new Moon can appear to completely blot out the disk of the Sun. On such occasions, the Moon is casting its dark, slender cone of shadow (called the umbra) upon the Earth’s surface; that shadow can sweep a third of the way around the Earth in just a few hours. Those who are positioned in the direct path of the umbra will see the Sun’s disk diminish into a crescent, while beneath that spectacle, the Moon’s shadow will be rushing toward them across the landscape. During the brief period of totality, when the Sun’s disk is completely obscured, they will be engulfed in an eerie semidarkness, quite different from the onset of darkness at the end of a sunny day.

Self-evidently, the phenomenon differs from a total lunar eclipse. That is not only because in one case the Sun is obscured from our view, and in the other the Moon; rather, they are obscured in different ways. Astronomically speaking, a solar eclipse can be called an occultation: a masking of a celestial body by another that passes in front of it. During a total lunar eclipse, in contrast, the full Moon passes completely into Earth’s shadow. From another point of view—that of an observer on the Moon, for instance —a total solar eclipse amounts to a partial (very partial) eclipse of the Earth.

Contrary to popular belief, total solar eclipses are not particularly rare. Astronomers predict sixty-eight to take place during the twenty-first century—one about every eighteen months. That’s not counting annular or “ring” eclipses (in which the Moon is too far from Earth to completely cover the Sun, and the tip of the umbra doesn’t quite reach Earth’s surface); hybrid eclipses (which are annular along one part of the path, total along the rest); and a goodly number of partial solar eclipses.

But if total solar eclipses aren’t all that rare, seeing one is—mainly because (even assuming clear weather) you have to be at the right place at just the right time, and the Sun and Moon do not arrange their assignations for human convenience. The track traced by the Moon’s umbra on Earth can run for many thousands of miles, but it’s also very narrow, at most about 170 miles wide. It has been calculated that on average, a total eclipse of the Sun is visible from the same spot on Earth only once in about every 375 years. If you think back to a time when human societies were small and communications and transportation limited, not only were the chances of seeing a total solar eclipse slight, but the fact that anyone else had ever seen one would not be common knowledge. The phenomenon would have been regarded with awe and, likely, fear—as a sign that the gods were angry, an omen of impending disaster. Many people believed that the Sun disappeared because it was being eaten by a dragon. And, of course, as soon as the priests—the only astronomers (or rather, astrologers) of the earliest civilizations—were able to forecast such happenings, they could use their skills as a means to impress the multitudes.

Design by Howard Russell Butler, published as a supplement to the July-August 1926 issue of Natural History, of a triptych for the “Proposed Hall of Astronomy at the American Museum of Natural History.” It features three solar eclipses that he had observed in the United States (left to right): Oregon, June 8, 1918; California, September 10, 1923; and Connecticut-New York, January 24, 1925. Butler painted the eclipses based on sketches and notes of the colors he made in the brief time allowed.

Old Chinese bone inscriptions provide one of the earliest records of an eclipse—probably the one that, by our Western calendric reckoning, occurred October 22, 2134 b.c. Hsi and Ho, astronomers to the Emperor Chung K’ang, had failed to predict that eclipse, and as the Sun faded, pandemonium broke loose. The Son of Heaven had his court astronomers decapitated.

And there is at least one apparent reference to an eclipse in the Bible. In Amos 8:9, we read: “I will cause the Sun to go down at noon, and I will darken the Earth in the clear day.” Most likely that was the Eclipse of Nineveh, which has been dated June 15, 763 b.c. An Assyrian tablet also attests to the event.

Modern-day astronomers have learned much by studying solar eclipses, such as determining the precise relative positions of the Sun, Moon, and Earth. Certain kinds of studies—especially measurements of the Sun’s searing corona—can best be made during a total solar eclipse. The corona, or crown of the Sun, is a delicate halo of pearly white light that is always present but whose pale glow is normally overpowered by the Sun’s brilliance. (Because it is only visible during totality, it wasn’t until the eighteenth century that astronomers were certain that the corona surrounded the Sun and not the Moon!) It’s composed of highly diffuse, superheated, ionized gases; most scientists believe those gases extend all the way to Earth as the solar wind. Thus, understanding the corona is relevant to understanding our own environment.

During a total solar eclipse, a few ruby-red spots may seem to hover around the jet-black disk of the Moon. Those are solar prominences, tongues of incandescent hydrogen gas rising above the surface of the Sun. During the total eclipse of August 18, 1868, the French astronomer Pierre Janssen trained his spectroscope on the prominences and discovered a new chemical element. Two English astronomers, J. Norman Lockyer and Edward Frankland, later named it “helium,” from the Greek helios (the Sun). The gas was not identified on Earth until 1895.

And because sunlight is blocked during a total eclipse, some of the brighter stars and planets can be observed in the darkened sky. Under such conditions astronomers were able to test part of Einstein’s now-celebrated general theory of relativity. That theory predicted that light from stars beyond the Sun would bend from a straight path in a certain way as it passed the Sun. The positions of stars photographed near the Sun’s edge during a total eclipse on May 29, 1919, were compared with photographs of the same region of the sky taken at night; the results strongly supported Einstein’s theory.

I’ve often been asked, why bother traveling to an eclipse? My answer is always the same: “You must see one for yourself, and then you will understand.” Astronomy writer Guy Ottewell planned to create a painting of the 1983 eclipse visible from Borobudur in Java. He later wrote: “During the minutes of totality I was conscious of being in a different visual world; of trying to memorize colors for which I had no names, which would be as hard to recall or describe as a taste.”

Although—or perhaps because—totality lasts for a brief time, there are some devoted eclipse chasers who organize their vacations, indeed much of their lives, and travel long distances so that they can witness as many eclipses as possible.

Total eclipse from 36,000 feet; darkened area lower right is Moon’s shadow on Earth.

Photo by Joe Rao
It takes dedication, because the Moon’s shadow seems to have a perverse habit of passing over unpopulated and inhospitable parts of our planet. And for those who have made extensive plans, an overcast sky on eclipse day can be devastating. But there is something we can do about the weather besides talk about it: take to the air!

One of the earliest attempts at an air-borne observation of an eclipse came over Russia on August 19, 1887, when Dmitri Mendeleev (better known for his work on the periodic table) carried out a solo balloon flight, ascending to 11,000 feet and landing two hours later after traveling 150 miles. And yes, he successfully observed the eclipse. The very first attempt to do so from an airplane took place June 8, 1918. The Scientific American later noted that while the flight was "not undertaken with any serious scientific objective in view, it was at least demonstrated that we may eventually look to the aviator for work of value in connection with eclipses."

When the January 24, 1925, eclipse passed over New York City, twenty-five aircraft went aloft to observe it. Spread out from New Haven, Connecticut, to Greenport, Long Island, they flew at various altitudes from 5,000 to 15,000 feet above patchy clouds. In all, fifty men witnessed totality from those planes, which all took off from the army’s now long-deactivated Mitchel Field on Long Island. In addition, the U.S.S. Los Angeles, then the largest dirigible in the world, took up a position nearly nineteen miles off Long Island’s Montauk Point. There, from 3,000 feet, the forty-two observers aboard had a clear view of the sky, whereas clouds at 2,000 feet would have obscured the eclipse from a ship at sea.

Another milestone came on June 20, 1955, when a T-33 jet flying at 38,000 feet and 600 miles per hour followed the eclipse path over Southeast Asia and the Philippines. That was the first real "eclipse chase" by an aircraft, extending the duration of totality to more than twelve minutes, compared with just over seven minutes for ground-based observers. That feat was eclipsed on June 30, 1973, when scientists aboard a Concorde jet flew at more than twice the speed of sound across Africa and enjoyed seventy-four minutes of totality.

Aircraft can also be useful for viewing an eclipse in hard-to-access regions, such as near the poles (though if you actually lived year-round within the Arctic or Antarctic Circle, the experience of an eclipse during the summer, when the sun never sets, would be extraordinary). The total solar eclipse of November 23, 2003, for example, was the very first in history to have been observed from the Antarctic.

So it was that on August 1, at 3:30 a.m. local time, I found myself at Düsseldorf International Airport, preparing to board an Airbus A330-200 long-range jet for a 2,189-mile airlift to a grandstand seat. The flight was arranged with LTU International Airlines by Deutsche Polarflug. There were 146 other participants, about half of them “umbraphiles” or “eclipsomaniacs”; the others were on board to take in the sights of the Arctic (of necessity, as only half the plane windows would be facing the solar spectacle). Most of us came already prepared, but special dark glasses were handed out, along with a warning against looking directly at the Sun during the partial stages of the eclipse.

Composite of five digital camera images of the eclipse of August 1, 2008, processed to bring out detailed structure that cannot be revealed in a single photograph. The shape of the corona resembles that in Butler’s painting of the eclipse of September 10, 1923 (center panel in the triptych above). Both eclipses occurred during quiescent years of the eleven-year sunspot cycle.

Images by Bill Kramer (www.eclipsechasers.com); composite by Glenn Schneider

We flew over the German North Sea coast and Denmark toward Norway. From there, we flew across the Barents Sea heading to Spitsbergen, the largest island of the Svalbard archipelago in the Arctic Ocean. The name Spitsbergen means "jagged peaks," and we found the name most fitting, for when we dropped from our cruising altitude of 36,000 feet down to 7,000 feet to have a closer look, we saw mountain formations, majestic fjords, and calving glaciers. Ascending again to 36,000 feet, we prepared for our special "totality run," just 500 miles from the North Pole. Astronomer Glenn Schneider, from the University of Arizona’s Steward Observatory, had worked out the flight plan for Captain Wilhelm Heinz and his flight crew. This was to be Schneider’s twenty-seventh total eclipse, and he hoped to collect new corona data.

Flying nearly seven miles above the Earth’s surface, our jet provided an unobstructed view above more than three-fourths of the atmosphere’s mass and almost all its water vapor. Several minutes before totality, the light inside the cabin gradually faded, signaling the start of a show much as the lights dim in a theater. Over the drone of the jet engines, passengers spoke excitedly in German and English as the Sun narrowed to a curved filament of light. As the last of its rays squeezed past the jagged lunar edge, they produced a beautiful and long-lasting “diamond ring” effect. The lunar shadow then swept in from the west and enveloped our plane in the eerie darkness of totality.

In the cobalt-blue sky the Sun’s corona now shone like a brilliant platinum ring on a dark velvet cushion. Several long streamers spilled out from the corona, a typical feature when the Sun is at sunspot minimum, as it is has been for the past couple of years. On the edge of the Moon’s jet-black disk, a small prominence could also be glimpsed. Adding to the scene, to the left of the darkened star of the show, four planets seized their chance to shine: Mercury, Venus, Saturn, and Mars. ?Although no match for the Moon’s shadow, which was moving at 2,740 miles per hour, our aircraft, with its 555-mile-per-hour speed, provided us with 175 seconds of total eclipse in which to take pictures and record other data. An observer on a stationary ship on the Arctic Ocean below us would have had 132 seconds.

Up front in the flight deck, Schneider had his camera equipment set up on a platform stabilized by two gyro-scopes. His experiments dealt in part with the density of plasma in the solar corona and the question of how it is heated to millions of degrees Fahrenheit. He was collaborating with Jay Pasachoff of Williams College in Massachusetts, who was stationed within the totality path at Akademgorodok, Siberia. They had collaborated on a similar observation during the Antarctic eclipse of 2003.

Those 175 seconds went fast: a second diamond ring blazed forth, and the corona quickly faded away. There was a sensation of released tension as a cacophony of

With temperatures hovering around freezing, gaps appear in the sea ice at the North Pole during the Arctic summer. The North Pole is significantly warmer than the South Pole because it lies at sea level in the middle of an ocean, which acts as a reservoir of heat; the South Pole falls within a continental land mass at an elevation of 9,300 feet.

Photo by Joe Rao

whoops and cheers greeted an eclipse flag that was paraded around the cabin. The owner of the flag was Craig Small, a colleague of mine at the Hayden Planetarium, who considers it his lucky charm. He has traveled to twenty-six eclipses and has never been clouded out!

After the eclipse, the rest of our journey was spent “flightseeing” over fields of pack ice interspersed with gaps of water and enormous icebergs. We counted down to our impending arrival at 90 degrees north latitude, and soon we were on top of the world. After flying directly above the North Pole, we circled it first clockwise and then counterclockwise, each time flying across all 360 degrees of longitude in just two minutes. From that point, the distance to northern Canada was only 465 miles, put-ting us closer to the American continent than to Europe.

As we headed back to Düsseldorf, many on the air-plane were comparing digital images and videos of the darkened Sun, and some were already making plans to chase the next eclipse, set for July 22, 2009. Totality will sweep over parts of India, China, and the Ryukyu Islands of Japan; in some locations it will last more than six minutes, the longest that celestial mechanics will allow until the year 2132.

One passenger perhaps summed it up best: “No pictures or words can ever convey the experience of totality. It’s something you feel; you just get hooked. I came here to be awed—and I am.”

Joe Rao Chief Meteorologist at News 12 Westchester, serving New York’s Hudson Valley, Joe Rao has been an assiduous amateur astronomer for more than forty years. Since 1986 he has been an instructor and guest lecturer at New York’s Hayden Planetarium. He has also co-led two eclipse expeditions and has served as onboard meteorologist for three eclipse ocean cruises. Rao is a regular contributor to Space.com and the Farmers’ Almanac and writes a Sunday feature, “Sky Watch,” for the New York Times. His column for Natural History has been a regular feature since January 1995.

Hear author Joe Rao interviewed by Vittorio Maestro,
Editor in Chief of Natural History (MP3, 24 min., 23 sec.)

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