DeVaucouleurs returned to Le Houga in July 1941, and without abandoning his lifelong interest in Mars he turned his attention to the measurement of close double stars, variable stars, and the brightness variations of the asteroid Eros.
DeVaucouleurs continued his association with the Péridier Observatory in Le Houga, applying the research done for his thesis to light scattering in the Earth's atmosphere.
Therefore, it was natural that deVaucouleurs should look at Frank Kerr's map of 21-cm velocity residuals across the Large Magellanic Cloud, and he was able to recognize the presence of a typical rotation pattern for a disk galaxy.