Robert Paul "Bob" Kraft (June 16, 1927 – May 26, 2015) was an American astronomer. He performed pioneering work on Cepheid variables, stellar rotation, novae, and the chemical evolution of the Milky Way. His name is also associated with the Kraft break: the abrupt change in the average rotation rate of main sequence stars around spectral type F8. Career Kraft served as director of the Lick Observatory (1981–1991), president of the American Astronomical Society (1974–1976), and president of the International Astronomical Union (1997–2000). He received his B.S. at the University of Washington in 1947, M.S. in mathematics at the University of Washington in 1949, and PhD from the University of California, Berkeley. He died in 2015. Honors Awards Helen B. Warner Prize for Astronomy (1962) Henry Norris Russell Lectureship (1995) Bruce Medal (2005) National Academy of Sciences Named after him Asteroid 3712 Kraft References Further reading External links Sandra Faber, "Robert P. Kraft", Biographical Memoirs of the National Academy of Sciences (2022) 1927 births 2015 deaths Members of the United States National Academy of Sciences 20th-century American astronomers 21st-century American astronomers Scientists from Seattle University of Washington alumni University of California, Berkeley alumni Presidents of the International Astronomical Union