Named in memory of Justo Ossaka (1922-1998), emeritus director of the Sendai Astronomical Observatory. Graduating from the Geophysical Institute, Tohoku University, in 1950, he worked at the Sendai Observatory from 1956 to 1994. He contributed greatly to attracting amateur astronomers and planetarium visitors. Name proposed by A. Watanabe and M. Koishikawa of the Sendai Astronomical Observatory.