Civil time
From Wikipedia, the free encyclopedia
Civil time is another name for mean solar time reckoned from midnight. Before 1925, the astronomical time 00:00:00 meant noon, twelve hours after the civil time 00:00:00 which meant midnight. HM Nautical Almanac Office in the United Kingdom used Greenwich Mean Time (GMT) for both conventions, leading to ambiguity, whereas the Nautical Almanac Office at the United States Naval Observatory used GMT for the pre-1925 convention and Greenwich Civil Time (GCT) for the post-1924 convention until 1952. In 1928, the International Astronomical Union introduced the term Universal Time for GMT beginning at midnight, but the two Nautical Almanac Offices did not accept it until 1952.
More recently this term is sometimes found with reference to specific statutory or standard time scales designated by civilian authorities, or with reference to local or standard time indicated by clocks. Generally speaking, the non-astronomical uses of this label are considered imprecise.
