Chief5130 Posted February 3, 2020 Report Share Posted February 3, 2020 I am currently on vacation and stopped in Greenwich for a visit. Below is the line that defines GMT. Time being important if you want to know your longitude. For many years it was a best guess and was expensive with ship wrecks when you did not. Having read the book Longitude, I had to go see the clocks that Mr. Harrison developed to solve the problem. He made 4 different clocks before he got it accurate and practical enough to work. The red ball on the top of the building is raised just before 1:00 GMT and dropped exactly at 1:00 pm. This is / was done so the ships can set their clocks to the exact time to use for navigation. Someone was selected to watch and record when the ball dropped. This is where the term "Keep you eye on the ball" comes from. If you are looking for a good read, I recommend Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time by Dave Sobel. You will have a new appreciation for you GPS. 3 Quote Link to comment Share on other sites More sharing options...
whichwaysup Posted February 3, 2020 Report Share Posted February 3, 2020 That is really cool. What are you standing on that has the country names? Looks like a track? Quote Link to comment Share on other sites More sharing options...
smilemaker Posted February 3, 2020 Report Share Posted February 3, 2020 My guess is 0 degree longitude 1 Quote Link to comment Share on other sites More sharing options...
Chief5130 Posted February 3, 2020 Author Report Share Posted February 3, 2020 Correct it is 0' Longitude in Greenwich England. Also GMT (Greenwich Mean Time). All Longitude is measured from this line. 1 Quote Link to comment Share on other sites More sharing options...
mustang190 Posted February 4, 2020 Report Share Posted February 4, 2020 Thats neat. I think it was the history channel that had the movie called "Longitude" about Harrison. In the Air Force we referred to Greenwich Mean Time as ZULU Time. Quote Link to comment Share on other sites More sharing options...
rckeat Posted February 4, 2020 Report Share Posted February 4, 2020 Cool story Tyson. Quote Link to comment Share on other sites More sharing options...
Big Dave Posted February 4, 2020 Report Share Posted February 4, 2020 Thanks for sharing that. Quote Link to comment Share on other sites More sharing options...
Big Dave Posted February 4, 2020 Report Share Posted February 4, 2020 My son told me he read that book when he was a student at the Maine Maritime Academy. Quote Link to comment Share on other sites More sharing options...
quest4reds Posted February 8, 2020 Report Share Posted February 8, 2020 Cool. Book ordered. Quote Link to comment Share on other sites More sharing options...
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