A (Not So) Brief History of Lunar Distances

Lunar Longitude Determination at Sea Before the Chronometer

Bibliographic Data

ID21715995
AuthorsRichard De Grijs (0000-0002-7203-5996, Macquarie University, corresponding author)
Year2020
Volume23
Issue3
Pages495-522
Publication date2020-12-01
Open AccessNo
TypeARTICLE
VenueJournal of Astronomical History and Heritage (JOURNAL)
Journal identifiersISSN: 1440-2807
PublisherChina Science Publishing & Media Ltd. (PUBLISHER)
DOI10.3724/sp.j.1440-2807.2020.03.04
OpenAlexW3045837014
LanguageEN
Citations received1
References cited9

Longitude determination at sea gained increasing commercial importance in the late Middle Ages, spawned by a commensurate increase in long-distance merchant shipping activity. Prior to the successful development of an accurate marine timepiece in the late-eighteenth century, marine navigators relied predominantly on the Moon for their time and longitude determinations. Lunar eclipses had been used for relative position determinations since Antiquity, but their rare occurrences precludes their routine use as reliable way markers. Measuring lunar distances, using the projected positions on the sky of the Moon and bright reference objects—the Sun or one or more bright stars—became the method of choice. It gained in profile and importance through the British Board of Longitude's endorsement in 1765 of the establishment of a Nautical Almanac . Numerous 'projectors' jumped onto the bandwagon, leading to a proliferation of lunar ephemeris tables. Chronometers became both more affordable and more commonplace by the mid-nineteenth century, signaling the beginning of the end for the lunar distance method as a means to determine one's longitude at sea

Apollo · Astrobiology · Geodesy · Latitude · Longitude · Moon landing · Physics · Historical Astronomy and Related Studies · Maritime and Coastal Archaeology · Travel Writing and Literature · Geology

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