James Edward Keeler (1857-1900), US astronomer. Keeler established a reputation as an outstanding spectroscopist, analysing the light emitted from astronomical objects. Using long-exposure photography he estimated that as many as 120,000 nebulae (later known as galaxies) could be detected in the night sky. In 1895 he analysed the spectrum of Saturn's rings, finding differing motions that showed that they were composed of numerous separate objects. In 1898 he was appointed director of the Lick Observatory, California, but died unexpectedly two years later. This image is from volume 8 (1900) of the US magazine Popular Astronomy.