In time to commemorate the 90th anniversary of Charles Lindbergh’s historic non-stop transatlantic flight in the “Spirit of St. Louis”, Longines is offering an updated version of its Lindbergh Hour Angle watch.

Notice the black bezel and dial insert hereThe original watch was designed for Longines by Lindbergh himself and was first introduced in 1931. Back then, its groundbreaking, rotating-bezel design allowed pilots and navigators to calculate their longitude during long-distance flights, thus allowing them to home in on their geographic location quickly, efficiently, and accurately.

Longines re-introduced the Lindbergh Hour Angle to its Heritage collection several years ago. This year, it adds the Lindbergh Hour Angle Watch 90th Anniversary, the first Hour Angle watch with a titanium case and limited to 90 pieces. It measures a hefty 47.5 mm in diameter, the idea being that a larger size would enable a pilot wearing the watch to more easily read and operate it in the dark, or while subjected to cockpit vibrations that were common to aircraft of the early 20th century.

Unlike the original and the reissue from a few years ago, the rotating bezel of this new watch is made of black PVD steel and features a galvanic black disk in the center of dial that rotates to synchronize the seconds with a radio time signal. The rotating bezel allows the wearer to adjust for the daily variations in the equation of time.

The original Lindbergh Hour Angle from 1931

The brushed silver dial displays the time on a railtrack minute circle with painted black Roman numerals, and features a 180° scale for calculating the longitude. The watch can thus be used to indicate the hour angle in degrees and in minutes of arc, as well displaying the current time in hours, minutes and seconds. The large, steel crown allows for easy winding of this movement, even while wearing gloves, a feature important to the aviators of yore.

The 90th Anniversary edition uses a modern, self-winding movement, Caliber L699. Based on the ETA A07.111 Valgranges, this 4 Hz movement was used in an earlier Hour Angle revival as well. The watch comes with a vintage-style brown leather strap, which is equipped with an extension that allows the watch to be worn over an oversized aviator’s jacket. The watch will retail at about $5,015.