Longines 18k Yellow Gold Lindberg Hour Angle 5230-608

An 18k Yellow Gold Lindbergh Hour Angle gents wristwatch, the two tone white and silver dial with roman numerals, 18k yellow gold bracelet, automatic movement, bi-directional rotating bezel, in excellent condition, comes with a presentation box, original bill of sale, and papers dated September 1989.The original Hour Angle watch was designed by Col. Charles Lindberg soon after his historic Trans-Atlantic flight in 1927, as an aid to navigation for pilots. The re-edition retains many of the original features of the original styling including the 'onion' winding crown and Breguet hands. The dial is also the same as the original with a duo-tone design, and an indication of longitude (in degrees & minutes), the central silvered dial originally rotating for the synchronization of the seconds hand with a radio time signal, the rotating bezel to allow adjustments to daily variations in the equation of time. When used in conjunction with a sextant and a radio to receive the time signal the original watch made it possible to determine the Greenwich hour angle i.e. Longitude.