The Longines Lindbergh Hour Angle Watch was first produced in 1931 as a celestial navigation instrument for pilots. Its turning bezel, engraved in degrees, measures the sun’s hour angle, and a rotating centre dial completes the navigation function, helping a navigator speed up longitude calculations over open ocean. It was boldly oversized for its time: WIPO gives the case as 47.5 mm, and a 1931 silver example sold by Phillips is listed at 47 mm, with an enamel dial, centre seconds, a slide rule and the manually wound calibre 18.69N. A large crown was designed to be operated with gloves. Longines registered the design in 1931 as an international design deposit under the Hague Agreement, with a certificate dated 29 September 1931. It matters as one of the first true navigation watches for aviation.

The watch grew out of Charles Lindbergh’s 1927 solo flight from New York to Paris, which exposed the risks of long-distance navigation. After getting lost near Cuba in 1928, Lindbergh turned to navigator Philip Van Horn Weems to sharpen his skills, then proposed a watch that could act as an aerial navigation instrument. In late 1930 he sent his drawings to John Heinmüller, president of the International Aviation Federation and director of Longines-Wittnauer in the United States. A first prototype was ready within five months, and production began the same year. The Hour Angle Watch was then used by a generation of pilots and navigators, and Lindbergh’s friend, French aviator Dieudonné Costes, is said by family tradition to have received one from him.

Collectors treat early Hour Angle watches as cornerstones of aviation watch history. The 1931 silver example associated with Costes, sold on 22 December 1931 to Longines’ French agent Perusset according to the archives, made CHF 143,000 at Phillips against an estimate of CHF 60,000 to 80,000. WIPO describes it as a revolutionary cockpit tool that integrated functions decades ahead of modern dive watches. The original 1931 model is no longer produced, but Longines has kept a modern 47.5 mm Lindbergh Hour Angle Watch in its heritage range, such as reference L2.678.4.11.0 with the automatic calibre L699. aBlogtoWatch praised its finishing and vintage aviator look, while noting that the 47.5 mm case is too large for many wrists.