Named for the Royal Greenwich Observatory on the occasion of the centennial of its adoption as the prime meridian for longitude and time. Founded by King Charles II in 1675 for the determination of longitude at sea, the Royal Observatory was soon established as one of the world’s leading astronomical research institutions. The prime meridian was agreed upon, after some dispute, at an international conference in Washington, D.C., on 1884 October 13. (M 8801) _ _.