Named in memory of Sakao Yamada (1918–1986), an outstanding Japanese engineer who devoted his life to the research and development of aspherical optics. Founder of Japan Special Optics, he made much optical equipment for Japanese amateur astronomers in cooperation with Nobuhisa Kojima {see planet  (4351)}, discoverer of two comets and 1973 MA, the first minor planet discovered by a Japanese amateur and one of the identifications for 1988 AE. Yamada, a teacher of both N. Kojima and the discoverer (no relation), pioneered the mass production of Schmidt-type cameras in Japan. With their high performance and capability, ease of handling and precise star images, these Schmidt cameras, which include the 0.25-m Wright Schmidt with which this discovery was made, have produced many splendid astro-photographs and discoveries of new heavenly bodies. (M 17028) _ _.