Born Cirey, Haute-Saône, France, 29 September 1904
Died Paris, France, 24 March 1978
While he contributed chiefly to the development and application of photomultipliers, André Lallemand also played important roles in the construction and instrumentation of French telescopes.
Lallemand was the son of Louis and Lucie Lallemand; his father was a primary-school teacher. Lallemand’s career in astronomy began in 1925 at the Strasbourg Observatory, where he served as an assistant to Ernest Esclangon . He qualified as a schoolteacher in the physical sciences in 1927 and taught at a high school in Haguenau, near Strasbourg, for a year. His doctoral research, which examined the magnetic properties of different elements of the iron family, was completed under Pierre Weiss at the Strasbourg Physical Institute. There, Lallemand acquired the experimental techniques that were essential for his later research on electronic detectors and amplifiers. He married Suzanne Ancel in 1928; the couple had two sons.
In 1928, Lallemand returned to the Strasbourg Observatory as aide-astronome, the level above an assistant. He devoted his energies to the improvement of astronomical observation methods. His infrared photographs of the solar corona, taken during an eclipse observed at Poulo Condore, Vietnam, in 1929, were in accord with the expected diffusion of light by photospheric electrons.
Lallemand’s interests then turned to astronomical photometry. In 1934, realization of the first photoelectric imaging devices led him to imagine what he called the “electronic telescope,” now known as the “electronic camera.” An optical image was first projected onto a photoelectric cell. The emitted electrons were then accelerated and refocused onto a photographic plate. The outbreak of World War II interrupted but also intensified research on these imaging devices. For several years, he and other scientists from the University of Strasbourg were moved to Clermont-Ferrand for defense-related work. In 1943, Lallemand accepted a joint appointment at the Paris Observatory and established a laboratory dedicated to improving photoelectric imaging devices for astrophysical observations.
In the 1950s, Lallemand collaborated on detector developments with Maurice Duchesne. The pair obtained a 100-fold gain in sensitivity as compared to ordinary photography. After 1952, numerous astronomical observations were made with this instrument, especially at the Haute-Provence Observatory. In 1953, Lallemand was named a senior astronomer at the Paris Observatory. In 1959, American astronomer Merle F. Walker invited Lallemand and Duchesne to install their electronic camera at the focus of the 120-in. reflector at the Lick Observatory. There, the trio first measured the differential rotation of the nucleus of M31 (the Andromeda Galaxy).
Many variations of this detector were constructed and utilized at observatories worldwide. In particular, Lallemand developed a wide-field camera with an 8-cm square photocell. Employed on the Canada-France-Hawaii telescope, it provided high-resolution views of the jet seen in the radio galaxy M87. Lallemand was appointed director of the Astrophysical Institute at Paris in 1960. The following year, he was awarded the chair of physical methods of astronomy at the Collège de France.
In the course of his career, Lallemand collected many honors and awards; among them were four prizes of the French Academy of Sciences. Along with his collaborator Duchesne, he received the prize of the French Conseil Supérieur de la Recherche Scientifique (1956). Lallemand was the recipient of the Eddington Medal of the Royal Astronomical Society (1962) and the Paul and Marie Stroobant Prize of the Royal Academy of Belgium (1962). He was made a Commander of the Legion of Honor (1964) and Grand Officer of the National Order of Merit (1968). The universities of Padua and Geneva bestowed honorary doctorates upon him. Lallemand’s name is attached to the prize awarded every 2 years to an astronomer by the French Academy of Sciences.
Lallemand was an officer of many important associations and committees. He served as president of the French National Committee on Astronomy (1963–1967), president of the French Society of Physics (1964), and president of the Bureau of Longitudes (1964). He likewise participated in the council to the European Southern Observatory [ESO] and the management of the Haute-Provence Observatory. Lallemand retired in 1974.