Throughout his career , A . -L . Breguet consistently demonstrated his exceptional mastery of time measurement . His strong involvement and his revolutionary developments earned him significant recognition and numerous honours . Renowned the length and breadth of Europe , Breguet found a particularly active admirer in Louis XVIII , king of France . In 1814 , the latter appointed him a member of the Bureau des longitudes in Paris . This body created in 1795 by the National Convention was dedicated to the advancement of the various branches of astronomy and their applications to geography , navigation and geodesy ( the measurement and understanding of Earth ’ s physical properties ). Its tasks included the annual publication of reference documents such as astronomical ephemerides .
The Bureau des longitudes was a prestigious organisation whose 20 or so members included geometers , astronomers , seafarers and associate artists . The only representative of his profession that was eminently useful to physicists and navigators , Breguet became the horological authority , notably for the calculation of longitudes at sea . As an extension of this distinction , through an ordinance issued on October 27th 1815 , Louis XVIII awarded A . -L . Breguet the official title of chronometer maker to the French Royal Navy .
This was the most prestigious title a horologist could hope to receive , given that the very concept of marine chronometry implied scientific knowledge . It also involved playing a crucial role for the country , as marine chronometers were of capital importance for fleets by making it possible to calculate ships ’ positions at sea .
Following in the wake of this unique heritage , the House of Breguet now launches a worldwide exclusive model named the Marine Équation Marchante 5887 . This “ Grande Complication ” marks the start of a new era for the contemporary Marine collection .
The equation of time is one of the rarest and most fascinating horological complications . It serves to display the difference between mean solar time , corresponding to civil or standard hours and minutes , and true solar time , meaning the actual solar hours and minutes .
Since Antiquity , the sun has been used as the basis of time . Nonetheless , the visible motion of the sun – the true solar time indicated on sundials – is irregular . With the improvement of timekeeping precision , watches and clocks became the basis of time and true solar time was replaced by mean solar time , within which each day has the same duration of exactly 24 hours .
Mean solar time may show a discrepancy with true solar time ranging from minus 16 minutes to plus 14 minutes . On just four days a year , the two times are exactly the same . Given that the sun ’ s various positions in the sky are reproduced in an identical manner on the same dates , watchmakers can “ program ” them by means of a special cam . The latter is shaped like a figure 8 and mechanically reproduces the path of the sun ’ s successive positions , called an analemma curve . Requiring extremely accurate execution , the cam is coupled with a feeler-spindle that drives an equation lever serving to indicate the difference between civil time and solar time ( -16 to + 14 minutes ). V
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