Caption:
Otto Wilhelm Struve (1819-1905) German astronomer, born at Dorpat. He followed his father, Friedrich Struve, as director of Pulkova Observatory near St Petersburg, Russia. Two of his sons became astronomers, and his grandson Otto became director of Yerkes and Macdonald observatories in the United States (1932). Lithograph. (Photo by: Universal History Archive/UIG via Getty Images)