An eclipse of the sun or moon on our planet Earth is very rare. I only remember two during my lifetime; I saw one of them clearly and clouds obscured the second one. That's because the full eclipse is visible only in a specific small part of the land. A partial eclipse is visible in a greater area.
For an eclipse to occur, the sun, moon, and earth need to be aligned properly so that one of them partially or completely shadows another. Wikipedia (online) states that this can happen twice yearly.
In Photographing the Eclipse of 1932 from the Air: From Five Miles Above the Earth's Surface, the National Geographic Society-Army Air Corps Survey Obtains Successful Photographs of the Moon's Shadow, Captain Albert W. Stevens first describes two failed attempts to photograph an eclipse from far above the earth's surface (National Geographic Magazine, November, 1932).
In addition to learning more about eclipses, this article has given me a deeper appreciation of our 2014 pressurized airplanes! In 1932, airplanes were flying experimentally only at altitudes of 39,000 feet where the temperature was 72 degrees below zero. Another problem is that "Oxygen, even if available as pure gas, is not absorbed properly by the blood under the conditions of lower atmospheric pressure," (p. 585). Why did these pilots want to fly so high? Because the shadow cast by an eclipse was so long that they wanted to capture it from high above.
Captain Stevens was the photographer. He and his pilot practiced the anticipated flight for many hours. It was to take place on August 31, 1932 at Fryeburg, Maine and surrounding area, including part of the State of New Hampshire. "Please remember that we had bitten off a rather large order: to photograph a spectacle approximately 100 miles across and 50 miles deep, moving at a speed greater than that of an army rifle bullet," (p. 588).
The best view of the eclipse was to be seen in the State of Maine. Captain Stevens and Lieutenant McAllister, the pilot, flew for 20 minutes and then spotted the eclipse. "The huge shadow, 100 miles across, swept toward us like a great bluish-gray wave, and the silvery white cloud tops became light gray, then dark gray, then almost black. . . The very instant that the last point of sunlight disappeared, the corona flashed out from around the black disk of the moon, exactly as if the sudden flipping of a switch. Although I had been present at other eclipses, I was awed by the situation," (p. 589).
What amazing photos the Captain took of the clouds but especially of the corona of the sun, at 5-second intervals!
FYI: Make your travel plans: the next total solar eclipse in the U.S.A. will happen in Carbondale, Illinois on August 21, 2017 for less than THREE MINUTES!
No comments:
Post a Comment