21. The solution came from a scorned carpenter, John Harrison, who perfected a precision marine chronometer in 1760. 22. One was his first marine chronometer project. 23. His technical advances enabled the quantity production of Marine Chronometers for use on board ships from around 1782. 24. The spring-driven marine chronometer is a precision timepiece used aboard ship to provide accurate time for celestial observations. 25. To put this in chronological context, in 1762 John Harrison's marine chronometer first enabled accurate measurement of longitude. 26. A plaque stands at number 120 commemorating Thomas Earnshaw's invention of the Marine chronometer , which facilitated long-distance travel. 27. The 3?longitude error may be explained by Carteret sailing without the benefit of the new marine chronometer . 28. The "'Omega Marine Chronometer "'was the first quartz wristwatch ever to be awarded certified status as a marine chronometer. 29. The "'Omega Marine Chronometer "'was the first quartz wristwatch ever to be awarded certified status as a marine chronometer . 30. The observatory's primary mission was to care for the United States Navy's marine chronometers , charts, and other navigational equipment.
