Athelstan Spilhaus’s “Sun Triangle” brings a scientific instrument to Midtown. Spilhaus, a geophysicist and meteorologist, designed and installed the sculpture so that the edges of the triangle would line up with the sun on equinoxes and solstices. On the summer solstice, the sun appears at the top of the triangle’s short side; in winter, it aligns with the lower leg. And on the first days of fall and spring, the sun lines up with the longest side of the triangle. Spilhaus was instrumental in bringing science to popular culture; his comic strip “Our New Age” explained scientific ideas, and was published from 1958 to 1973. He also joined with the architect Buckminster Fuller in an attempt to make the futurist “Minnesota Experimental City,” which was never built. Spilhaus contributed to the 1962 Seattle World’s Fair as the head of the United States’ exhibition.