American astronomer. Ph.D. mathematics, University of California, Berkeley (1927). Professional experience includes: instructor in mathematics, University of Illinois in Urbana-Champaign (1927-1929); Guggenheim fellow, Royal Greenwich Observatory (1929-1930); assistant professor of mathematics, associate professor of astronomy, director of Ladd Observatory, chairman of the Department of Astronomy, professor, Brown University (1930-1977); wrote popular column, "Planets and Stars," in the Providence Journal (1938-1957); fellow, Royal Astronomical Society; fellow, American Association for the Advancement of Science; president, American Association of Variable Star Observers; member of the editorial advisory board, Sky & Telescope (1941-1959). He led fourteen solar eclipse expeditions, in Peru, Canada, Brazil, Thailand, Pakistan, and the United States. On one occasion in 1963 he flew in a U.S. Air Force jet at 48,000 feet, racing the moons shadow to view a lunar eclipse longer than any other observer.