August Herman Pfund
|August Herman Pfund|
December 28, 1879|
|Died||January 4, 1949(aged 69)|
|Institutions||Johns Hopkins University|
|Alma mater||Johns Hopkins University
University of Wisconsin–Madison
|Doctoral advisor||Robert W. Wood|
|Known for||Pfund line
Pfund sky compass
Edward Longstreth Medal (1922)Frederic Ives Medal (1939)
Early life 
Pfund was born in Madison, Wisconsin and attended Wisconsin public schools until his entry into the University of Wisconsin–Madison, where he earned a B.S. degree in physics and studied under Robert W. Wood.
Both Wood and Pfund left Wisconsin for Johns Hopkins in 1903. From 1903 to 1905 Pfund was a Carnegie research assistant and continued to work under Wood. In 1906 Pfund earned his Ph.D. in physics and was a Johnston scholar from 1907 to 1909. He remained at Hopkins for the remainder of his career, eventually becoming a full professor and later chair of the physics department. From 1943 to 1944 Pfund served as the president of the Optical Society of America.
Pfund discovered the hydrogen spectral series or Pfund lines, where an electron jumps up from or drops down to the fifth fundamental level. He also invented the Pfund telescope, which is a method for achieving a fixed telescope focal point regardless of where the telescope line of sight is positioned, and the Pfund sky compass, which greatly helped transpolar flights by allowing the determination of the Sun's direction in twilight. Pfund is also noted for is work into the area of infrared gas analysis.
See also 
- Niels Bohr Library and Archives
- Presidents of the Late 1940s, John Howard, Optics and Photonics News, June 2010, last accessed 2013-04-08.
- Articles Published by early OSA Presidents Journal of the Optical Society of America
References and Biography 
- Pelletier, Paul A. (ed.), Prominent Scientists: An index to collective biographies, 2nd ed., Neal-Schuman Publishing, Inc.: New York, 1985 (citations only)
- Cattell, J.M.; Cattell, J. American Men of Science, 6th ed., The Science Press: New York, 1938
- Journal of the Optical Society of America, 39:4 (April, 1949) 325. Obit.
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