70th Anniversary of Beijing Time---The Establishment of Universal Time System

70th Anniversary of BeiJing Time---Shahe Workstation of National Astronomical Observatories

70th Anniversary of Beijing Time---Shanghai Astronomical Observatory

70th Anniversary of Beijing Time---Tsingtao Observatory

70th Anniversary of Beijing Time---Hong Kong Observatory

70th Anniversary of Beijing Time-Xujiahui Observatory

70th Anniversary of Beijing Time---The Birth of Beijing Time