Named in memory of William Albert Hiltner (1914–1991), discoverer of the interstellar polarization of starlight, an early practitioner of precision stellar photometry, and pioneering observer of the optical counterparts of celestial x-ray sources. Director of the Yerkes Observatory for many years, while there he designed and built a rotatable telescope for polarization studies and developed photometric instrumentation. As director of the University of Michigan’s observatory, he established the Michigan-Dartmouth-M.I.T. Observatory, led the construction of the 2.4-m telescope that is now named for him, and designed and constructed astronomical instrumentation. He also served as acting director of the Cerro Tololo Interamerican Observatory and as president of AURA. (M 20162) _ _.