2020/07/28 by Richard de Grijs, de Grijs, Richard · 1 citation
Physics and Astronomy · Social Sciences · #FOS: Physical sciences #Historical Astronomy and Related Studies #Historical Geography and Cartography #History and Developments in Astronomy #History and Philosophy of Physics (physics.hist-ph)
paper · pdf · doi:10.48550/arxiv.2007.14504
openalex publication_date 2020/07/28 · openalex created_date 2023/02/03 · openalex updated_date 2026/07/28
Longitude determination at sea gained increasing commercial importance in the\nlate Middle Ages, spawned by a commensurate increase in long-distance merchant\nshipping activity. Prior to the successful development of an accurate marine\ntimepiece in the late-eighteenth century, marine navigators relied\npredominantly on the Moon for their time and longitude determinations. Lunar\neclipses had been used for relative position determinations since Antiquity,\nbut their rare occurrences precludes their routine use as reliable way markers.\nMeasuring lunar distances, using the projected positions on the sky of the Moon\nand bright reference objects--the Sun or one or more bright stars--became the\nmethod of choice. It gained in profile and importance through the British Board\nof Longitude's endorsement in 1765 of the establishment of a Nautical Almanac.\nNumerous 'projectors' jumped onto the bandwagon, leading to a proliferation of\nlunar ephemeris tables. Chronometers became both more affordable and more\ncommonplace by the mid-nineteenth century, signaling the beginning of the end\nfor the lunar distance method as a means to determine one's longitude at sea.\n