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. 

 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 

 I besides talk about it: take to the air! 



One of the earliest attempts at an air- 

 Z borne observation of an eclipse came over 



0 Russia on August 19, 1887, when Dmitri 

 § Mendeleev (better known for his work on 

 § the periodic table) carried out a solo balloon 



1 flight, ascending to 11,000 feet and landing 

 < two hours later after traveling 150 miles. And 

 f yes, he successfully observed the eclipse. The 

 3 very first attempt to do so from an airplane 

 I took place June 8, 1918. The Scientific 

 I American later noted that while the flight was 

 | "not undertaken with any serious scientific 

 d objective in view, it was at least demonstrated 



ItD J * 



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 aT-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-tour 

 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 w ithin the Arctic or Antarctic 

 Circle, the experience of an eclipse during the summer. 



October 2008 NATURA1 HISTOU.Y 



39 



