Karl Kessler was born on Aug. 21, 1919, in Hamburg, Germany, and came to the U. S. with his family in 1926. They settled in Ann Arbor, Mich. Kessler attended the University of Michigan where he earned doctorate in physics in 1947.

Kessler went to work at the National Bureau of Standards (NBS) in 1948 as a physicist and focused on atomic spectroscopy and optical metrology. Among his accomplishments, writing the first computer program to analyze atomic spectra. He also became an internationally recognized expert on atomic spectroscopy and optical metrology.

Kessler’s abilities helped him move quickly up the management ladder. In 1959 he succeeded William Meggers as chief of the atomic spectroscopy group. Three years later he became chief of the atomic physics division and, then, in 1970, chief of the optical physics division. In 1977 he became director of the Center of Absolute Physical Quantities and served in that capacity until 1982.  Kessler then started a four-year stint as director of the Center for Basic Standards. In 1986 he was appointed associate director for international and academic programs, a position he held until his retirement in 1990.

Kessler’s achievements were recognized by various awards including an exceptional service award from the U.S. Department of Commerce and the Allen V. Astin Measurement Science Award. He also received OSA’s Distinguished Service Award. He was a fellow of OSA and APS and a member of the American Astronomical Society, American Association for the Advancement of Science, and the International Astronomical Union.

Karl G. Kessler died 7 July 1997.