The future of timekeeping is changing with the development of optical frequency standards and the resulting challenges of distributing time at ever higher precision, with the possibility of timescales based on pulsars, and with the inclusion of higher-order relativistic effects. The definition of the second will likely be changed before the end of this decade, and its realization will increase in accuracy; the definition of the day is no longer obvious.

We propose a symposium setting the stage for future timekeeping standards, infrastructure, and engineering best practices for astronomers and the broader society.

Hosted by the Harvard-Smithsonian Center for Astrophysics (CFA) in Cambridge, MA (USA). The CFA is a collaboration of the Smithsonian Astrophysical Observatory (SAO) and the Harvard College Observatory (HCO).