historicallywhy was longitude a harder problem to solve for navigators than latitudejedishrfu said:Thanks for sharing. John Harrison's legacy really revolutionized maritime navigation. It's hard to imagine what we'd be doing today without it.
https://en.wikipedia.org/wiki/John_Harrison
https://en.wikipedia.org/wiki/Longitude_(book)
and NOVA did show on his work based on the Sobel's book Longitude.
Why was longitude determination such a difficult problem compared with finding latitude? A very basic answer is that latitude is measured north or south and so is independent of the Earth's east-west rotation, whereas longitude's determination by celestial means is affected by that rotation. Latitude can be found, in principle, from angular measures alone—say the angle of the midday sun above the horizon—but longitude requires knowledge of time. Thus if a mariner had a clock keeping Greenwich time and found that it read 2 p.m. when the sun was at its maximum angle above the horizon—the local noon—he would know that his longitude was two hours west of Greenwich. The whole problem lay in finding a clock that would keep time with sufficient accuracy over the long voyages of the 17th and 18th centuries. The best timekeepers of the age were pendulum clocks, but these were useless on the heaving deck of a small ship, whereas spring-wound clocks were relatively crude and hopelessly inaccurate for voyages over many weeks or months.
Sydney, Australia Then back to EnglandAstronuc said:http://www.mysticseaport.org/ships-clocks-stars/
Exhibition produced by the National Maritime Museum, London
I wish that I had known about it. Where will the exhibit go from there?
"The clocks of John Harrison" refer to a series of timepieces invented by John Harrison in the 18th century. These clocks, known as marine chronometers, were crucial for accurate timekeeping and navigation at sea.
"The clocks of John Harrison" were important because they revolutionized navigation at sea. Before their invention, sailors had to rely on less accurate methods of determining longitude, which often led to shipwrecks and lost voyages. The marine chronometers allowed for precise measurement of time, thus enabling accurate navigation and safer sea travel.
John Harrison was a self-taught clockmaker who became obsessed with solving the problem of determining longitude at sea. He spent decades studying, experimenting, and refining his designs until he finally created a reliable marine chronometer that could withstand the conditions of a ship at sea.
"The clocks of John Harrison" are significant in the history of science because they represent a major breakthrough in timekeeping and navigation. Harrison's inventions were crucial for the Age of Exploration and had a significant impact on global trade and travel. They also demonstrated the power of scientific inquiry and the potential for human ingenuity to solve complex problems.
Yes, several of "The clocks of John Harrison" are still in existence and are considered valuable artifacts. The most famous is the H4, which is on display at the National Maritime Museum in Greenwich, England. Other clocks can be found in museums and private collections around the world.