Born: April 6, 1890; Caen, France Died: April 21, 1967; Paris, France Area of Achievement: Astronomy Contribution: Danjon primarily worked to increase

the precision of astronomical instruments in observing stars. The invention of the prismatic 60 degree astrolabe, or the Danjon astrolabe, is his crowning achievement. Toward the end of his career, in the 1950's, he also investigated irregularities in the rotation of Earth.