Born Opladen, (Nordrhein-Westfalen), Germany, 23 June 1901
Died Göttingen, Nordrhein-Westfalen (Germany), 13 May 1983
German mathematician and astronomer Otto Heckmann was instrumental in founding the European Southern Observatory [ESO], of which he was the first director, and also wrote a text in theoretical cosmology that guided a generation of researchers in German-speaking countries.
After completing Gymnasium in the Rhineland, Heckmann entered the University of Bonn, completing a doctorate in 1925 with a thesis on the positions and proper motions of stars in the nearby cluster Praesepe, using plates taken at Bonn and under the directorship of Karl Küstner . That same year he married Johanna (née) Topfmeier who predeceased him by 2 years; they had three children.
For two additional years at Bonn, Heckmann worked on the theory of the dynamics of star clusters. (One of the important implications of his thesis observations and that theory is that clusters like Praesepe will dissipate after about 108 years.) Heckmann was then appointed to the faculty and observatory staff at Göttingen, from which he returned to Bonn as professor and director in 1942, holding that position until 1962 and remaining in Hamburg during his term (1962–1969) as director general of ESO. He retired to Reinbek, West Germany, and returned to Göttingen later in life.
During his terms in Göttingen and Hamburg, Heckmann came to fully appreciate the impossibility of pursuing certain kinds of astronomy under European skies. As a result, first, he focused observatory efforts on those things that could be done, most importantly the vital astrographic catalog AGK (with proper motions for 180,000 stars), coordinated from Bonn, but with contributions from a dozen other European observatories.
Second, Heckmann turned some of his own attention to theoretical problems, especially during the difficult years of World War II, publishing Theorien der Kosmologie in 1942. After the war he worked sporadically on general relativistic models of the Universe with strong anisotropies, which are sometimes collectively called Heckmann-Schucking-Behr cosmologies, partly with Engelburt Schucking and Alfred Behr.
Third, and perhaps most important, Heckmann joined with astronomical leaders in the Netherlands ( Jan Oort ), Sweden ( Bertil Lindblad ), and France ( André Danjon , P. Bourgeois) to establish plans for a joint European observatory in the Southern Hemisphere, under the clear skies of Chile, and persuaded their governments to provide sufficient collective funding to establish a facility there and construct an initial set of telescopes, cameras, and spectrographs. Heckmann himself had been partly responsible for the design of the Hamburg 1.2-m Schmidt, and was actively involved at all stages. The English Astronomer Royal of the time, Harold Spencer Jones , was also part of these discussions, but the United Kingdom decided to remain outside the ESO until more than 30 years later.
During the latter part of his ESO directorship, Heckmann was also president of the International Astronomical Union (1967–1970), and he had previously led both the astronomical and general science societies of Germany. He received honorary doctorates from Marseilles, La Plata, and Sussex and was a member or foreign associate of 11 academies of science. Heckmann received the Watson Medal of the US National Academy of Sciences, the Janssen Medal of the Société Astronomique de France, and the Bruce Medal of the Astronomical Society of the Pacific. Minor planet (1650) is named in his honor.