 During the flyby, the spacecraft imaged a hemisphere of the asteroid, revealing many large craters that had gouged out depressions in the surface.It was the first carbonaceous asteroid to be explored and, until 21 Lutetia was visited in 2010, was the largest asteroid to be visited by a spacecraft.In 1880, Johann Palisa, the director of the Austrian Naval Observatory , was offered a position as an assistant at the newly completed Vienna Observatory.