Galilei had spent endless nights to obtain observations of Jupiter's moons with the highest possible accuracy. His motivation had been the hope to develop a celestial clock for the determination of latitude. He had already designed an observer's chair for use on ships.
Huygens had the same aim when he experimented with the pendulum, hoping to be able to use it for accurate time keeping. His idea was pointing in the right direction, but clocks on ships travel through many climate zones, and Huygens did never achieve complete temperature compensation; his pendulum expanded in the tropics, which made it slow down, and got shorter in the cold, which made it speed up.
Robert Hooke and Gottfried Leibnitz also worked on the latitude problem, both without success.
The problem was solved in 1714 not by a scientist but by a craftsman, the carpenter and self-taught watchmaker John Harrison. The fourth version of his chronometer won him the reward of 20,000 pounds offered by the British government for anyone who could find a method for the detection of latitude at sea, accurate to within 30 nautical miles after a six week long voyage.