Named in memory of Paul Sollenberger (1891–1995), the U.S. Naval Observatory’s first civilian director of Time Service (from 1928 until his retirement in 1953). Sollenberger’s contributions to the design of quartz-crystal clocks, chronographs and the photographic zenith tube greatly increased the precision of timekeeping during his tenure. By 1934 he had not only introduced quartz-crystal clocks, but also arranged for the automatic transmission of time by them, accurate to a millisecond. In 1949 he established the USNO’s Time Service station using a PZT in Richmond, Florida. Sollenberger served as president of IAU Commission 19 during 1948–1955. (M 25653) _ _.