Harold Eugene "Doc" Edgerton (April 6, 1903 - January 4, 1990) was an electrical engineer, MIT professor, co-founder of the EG&G company, and most famously, a pioneer in high-speed photography and the visualization of high-speed phenomena.

Edgerton was born in Fremont, Nebraska to parents Frank and Mary Edgerton. Edgerton first learned about photography from his uncle as a teenager, but he eventually took up electrical engineering at the University of Nebraska after summer jobs with his local electrical company. He graduated from there in 1925, moved to Schenectady, New York to continue working in the electrical industry, and then enrolled at MIT for graduate studies. He was awarded his Master's Degree in 1927 for his thesis on stroboscopic imaging of motors, and finished his Doctorate in 1931. He became a member of the faculty at MIT at that time.

In the 1930's, Edgerton began his most famous work, using a stroboscopic camera to photograph high-speed phenomena. In this technique, a camera with a high-speed shutter is coupled to a very bright, fast strobe light. The camera is triggered in such a way as to catch the event as it is happening, usually using a piezoelectric microphone or a light detector as the switch. In this way, Edgerton was able to catch the fine details of rapid events like the splash of a milk droplet, or a bullet piercing a balloon, an apple, or a playing card. Edgerton also began using multiple, rapid strobe flashes on a single exposure to capture motion (for example, a golfer swinging a driver). In this way, he was able to bring out the fine details of dynamical phenomena for human study. In 1940, Edgerton et al. worked on a short film, Quicker Than A Wink, which won an Academy Award for best short film that year.

In the late 1930's and 1940's, Edgerton, along with Kenneth Germeshausen and Herbert Grier (two of Edgerton's students at MIT) began a long affiliation with the United States military, eventually forming the company EG&G in 1947. In 1939, they developed very powerful camera flashes to be used from airplanes for night-time reconnaissance and aerial photography. This system was used several times during World War II, including D-Day.

EG&G was also involved with nuclear weapons design and research. First, EG&G supplied the triggering system which detonated the device. The proper detonation of an atomic bomb requires that the core of the device implode rapidly and in as spherically symmetric way as possible. Therefore, the high explosive jacket covering the fissionable material has to be detonated at multiple points within much less than a microsecond of one another. EG&G also supplied the photographic equipment which allowed scientists to film nuclear tests at very early stages of the explosion. One striking photograph of the early moments of a nuclear test shows a fireball only a few hundred feet across, not yet large enough to engulf the tower from which it was fired. Such photographs require extremely fast exposure times -- much less than a microsecond, and new technology had to be used. For example, their Rapitronic cameras used magnetic shutters rather than mechanical ones, because mechanical parts could not work at the speeds required. The shutter has no moving parts -- it works by passing a magnetic field between two crossed polarizing filters. A brief magnetic pulse causes Faraday rotation in the incoming light, allowing it to pass through the normally opaque second filter. They also developed motion picture cameras capable of recording millions of frames per second, in order to record the progress of explosions in fine detail.

Edgerton is also famous for his work on underwater photography and sonar, including collaborations with Jacques Cousteau. He worked with Cousteau starting in 1953, to develop underwater cameras which used sonar as a rangefinder near the ocean floor. He also worked on side-scan sonar, and a low-frequency sonar capable of penetrating the ocean floor to search for buried rocks and debris. He helped to explore the sunken Achaean city of Helice in 1966, and in 1973 helped to find the U.S.S. Monitor off Cape Hatteras in North Carolina. His penetrating sonar was used to find the English warship The Mary Rose dating from the reign of King Henry VIII, which accidentally sank in 1545 during an engagement with the French navy in the English Channel.

Edgerton retired from EG&G in 1975, though he remained affiliated both with the company and with MIT until his death. He died in 1990 of a heart attack while dining at the faculty club at MIT. During his life, he received several awards for his work, including an Academy Award (1940), the War Department Medal of Freedom for his work on aerial reconnaissance, the National Medal of Science in 1973.

Sources: Most of the biographical information was obtained from the web biography at http://www.edgerton.org/biography.html, and from http://www.egginc.com/. The rest is from (somewhat fuzzy) memory.

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