Russian–German family which produced four generations of astronomers. The most important were: F. G. W. von Struve; his son Otto W. Struve (Otto I); and Otto I’s grandson Otto Struve (Otto II). Karl Hermann Struve (1854–1920) was the elder son of Otto I. He refined the orbits of several satellites and studied Saturn’s rings. Gustav Wilhelm Ludwig Struve (1858–1920), the younger son of Otto I and the father of Otto II, continued his father’s work on the motion of the Solar System and studied lunar occultations. Georg Struve (1886–1933), Hermann’s son, also studied the Solar System, notably the satellites of Saturn and Uranus.