Patent ID: 6947351

Claim:
A watch intended for defining a location longitude, comprising a case ( 10 ) closed by a back cover ( 40 ), in which are disposed a wheel ( 16 ) completing one revolution in 12 hours and carrying an hour hand ( 24 ), a wheel ( 18 ) completing one revolution in one hour and carrying a minute hand ( 28 ), and a dial ( 32 ), characterised in that it further includes: a rotatable ring ( 44 ) for reading longitude, bearing an origin ( 47 ) and, therefrom, a longitude scale ( 45 ) in degrees covering 180° over the periphery of the longitude scale ( 45 ), in that the dial ( 32 ) is equipped with a time zone scale ( 33 ) for selecting a time zone, with a median point ( 35 ) corresponding to the top point of the dial, the time zone scale ( 33 ) covering 12 hours over the periphery of the time zone scale ( 33 ), each hour on the time zone scale ( 33 ) representing 15° on the longitude scale ( 45 ), and, when the origin ( 47 ) is aligned with the median point ( 35 ), the value of a number on the longitude scale ( 45 ) being equal to an absolute value of the opposing hour mark on the time zone scale ( 33 ); and a calendar indicator ( 54 ) in polar co-ordinates, with an angular indication of the months and days of the year and a radial indication in the shape of a curve ( 50 ) relative to the equation of time, and an index ( 48 ) mounted to move in rotation opposite the calendar indicator ( 54 ) and bearing a reading scale ( 52 ) for determining the equation of time.