Legendary lunar and planetary observer Walter Haas (1917-2015) died on 2015 April 6. Haas was renowned for the skill, integrity, and intelligence he brought to the serious observation of solar-system objects. He also possessed effective organizational and leadership skills, which bore fruit in the founding and sustaining of the Association of Lunar and Planetary Observers (ALPO, 1947-), one of the outstanding organizations fostering meaningful amateur solar-system work.