Named in memory of Horace E. Dall (1901–1986), a talented craftsman known internationally for his skill in instrument making, optics and optical design. Inventor of the Dall ‘null’ test for parabolic telescope mirrors and coinventor of the Dall-Kirkham Cassegrain-type telescope, Dall was well known for his Maksutov telescopes, in particular a six-inch-aperture folding model that he used to take on his world travels. Dall refigured many telescope objective lenses to give optimum resolution, and he was also well known for making high-power microscope objectives. Dall joined the British Astronomical Association in 1925 and was awarded its Walter Goodacre Medal in 1967. (M 25231) _ _.