Audouin Charles Dollfus, was a French astronomer, physicist and aeronaut born in Paris on 12 November 1924. He was the son of Charles Dollfus, a noted aeronaut, aviation historian, and long-time curator of the Musée de l'Air. Growing up in an environment shaped by aviation and scientific curiosity, he built his first refracting telescope at the age of fourteen and joined the Société Astronomique de France in 1941, beginning a lifelong association with both professional and amateur astronomy.

After graduating in mathematical sciences and physics in Paris, Dollfus joined the Meudon Observatory in 1945, where he entered the laboratory of Bernard Lyot, one of the pioneers of modern astronomical optics. His first professional observations were carried out the same year at the Pic du Midi Observatory, and during the 1948 opposition of Mars he produced his first major scientific publication, providing new evidence against the long-standing "Martian canal" interpretation. He remained associated with the Paris Observatory throughout his career, eventually becoming head of the Laboratory for Physics of the Solar System and directing the Centre for Planetary Documentation at Meudon from 1961 to 1980. Under his leadership, the center assembled one of the world's largest collections of planetary photographs, promoting international collaboration and providing an essential archive for comparative studies of the planets.

Dollfus became one of the world's leading specialists in planetary polarimetry, using polarized light to investigate the physical properties of planetary surfaces and atmospheres. His studies of Mars established methods for distinguishing bare ground, atmospheric dust, and clouds, and helped determine the characteristics of dust particles suspended during global storms. Long before spacecraft reached the planet, he concluded that the bright Martian deserts were covered by finely divided iron-rich material, an interpretation later confirmed by the Viking landers. His investigations extended to Mercury, Venus, the Moon, and the satellites of the outer planets, combining careful visual observation with innovative optical techniques.

His research on the Moon demonstrated that its surface consisted largely of fine pulverized basalt, providing valuable information for the planning of future lunar landings. NASA invited him to participate in studies of the Apollo 11 landing site, to advise on the design of astronauts' lunar boots, and to analyze samples returned by the Apollo missions. He also collaborated with NASA on the Ranger and Mariner programs and with the Soviet Mars-5 mission, contributing to the interpretation of planetary surfaces and atmospheres during the formative years of space exploration.

Dollfus combined astronomy with scientific ballooning through a remarkable series of balloon flights.

In 1956 he ascended to approximately 6,000 meters to obtain high-resolution photographs of solar granulation, helping demonstrate that convection, rather than atmospheric turbulence, governed the observed structure.

In 1959 he reached an altitude of about 14,000 meters in a pressurized gondola, setting a French altitude record that remained unsurpassed for decades. During this flight he obtained observations interpreted as evidence for water vapor in the atmosphere of Mars, illustrating his willingness to use unconventional methods to overcome the limitations imposed by Earth's atmosphere.

His observational achievements extended beyond the terrestrial planets. During a photographic search for faint Saturnian satellites, he discovered the moon Janus in 1966 and identified a faint outer ring of Saturn. Together with John B. Murray, he produced one of the most accurate telescopic albedo maps of Mercury before the arrival of spacecraft, and his extensive observations of Venus contributed to studies of the planet's cloud circulation. Throughout his career he published approximately 330 scientific papers and authored influential chapters in major reference works on planetary science.

Dollfus also played a significant international role within the astronomical community. As chairman of the International Astronomical Union's Commission on the Physical Study of Planets and Satellites, he helped establish a standardized map of Mars and contributed to the development of the modern nomenclature for Martian surface features. He remained deeply committed to historical astronomy, producing important studies of historic telescopes and participating in reconstructions of early astronomical instruments. He actively encouraged amateur astronomers, frequently sharing observatory facilities and promoting cooperation between amateur and professional observers.

His scientific accomplishments were recognized through numerous distinctions, including election as Chevalier of the Legion of Honour in 1989, the Prix Janssen of the Société Astronomique de France, the Galabert Astronautical Prize in 1973, and the Grand Prize of the French Academy of Sciences in 1988. Asteroid 2451 Dollfus was named in his honor, and he was elected an Honorary Fellow of the Royal Astronomical Society.

Dollfus died on 1 October 2010 in Versailles, France, at the age of 85.