Nautical time to the zero zone, and A–M (except J) to the east and N–Y to the west (J may be assigned to local time in non-nautical applications — zones M and Y have the same clock time but differ by 24 hours: a full day). These can be vocalized using the NATO phonetic alphabet which pronounces the letter "Z" as "Zulu", leading to the use of the term "Zulu Time" for Greenwich Mean Time, or UT1 from January 1, 1972 onward. Zone Z runs from 7°30′W to 7°30′E longitude, while zone A runs from 7°30′E to 22°30′E longitude, etc. These nautical
History of longitude European and North American longitude measurement campaigns in the 1850s and 1860s, resulting in improved map accuracy and navigation safety. Synchronization by radio followed in the early 20th century. In the 1970s, the use of satellites was developed to more precisely measure geographic coordinates (GPS). In the process of searching for a solution to the problem of determining longitude, many scientists added to the knowledge of astronomy and physics. History of longitude The history of longitude is a record of the effort, by astronomers, cartographers and navigators over several centuries, to discover a means of determining longitude. The measurement of