In the early 18th century the battle was on to improve the determination of longitude at sea , leading to the development of the marine chronometer by John Harrison . But it was the development of accurate star charts , principally by the first British Astronomer Royal , John Flamsteed between 1680 and 1719 and disseminated by his successor Edmund Halley , that enabled navigators to use the lunar method of determining longitude more accurately using the octant developed by Thomas Godfrey and John Hadley . Between 1765 and 1811 , Nevil Maskelyne published 49 issues of the Nautical Almanac based on the meridian of the Royal Observatory , Greenwich . " Maskelyne 's tables not only made the lunar method practicable , they also made the Greenwich meridian the universal reference point . Even the French translations of the '' Nautical Almanac '' retained Maskelyne 's calculations from Greenwich — in spite of the fact that every other table in the '' Connaissance des Temps '' considered the Paris meridian as the prime . " In 1884 , at the International Meridian Conference in Washington , D.C. , 22 countries voted to adopt the Greenwich meridian as the prime meridian of the world . The French argued for a neutral line , mentioning the Azores and the Bering Strait , but eventually abstained and continued to use the Paris meridian until 1911
International Meridian Conference
International Meridian Conference
Prime meridian