Seth Carlo Chandler, Jr.: Discoveries in polar motion

On January 1, 1988, the new International Earth Rotation Service (IERS) will become operational. IERS will encompass the services provided by the International Latitude Service (ILS), the International Polar Motion Service (IPMS), and the Bureau International de l'Heure (BIH) for nearly a century and will provide improved services that will be particularly useful to scientific researchers. For example, the IERS will establish and maintain a conventional celestial reference frame defined by a selected set of extragalactic radio sources, establish and maintain a conventional terrestrial reference frame defined by a set of globally distributed stations marked by monuments, determine improved constants of precession and nutation, and collect and distribute ancillary data important to understanding earth rotation, such as atmospheric angular momentum time series.