Lindbergh Hour-Angle

Lindbergh Hour-Angle, Second Generation Longines, "Lindbergh", movement No. 7298514, case No. 23472. Delivered to LonginesWittnauerWatch & Co., New York, on June 28th, 1948 . Fine, very rare and unusual, large, hour-angle, indirect center seconds, stainless steel aviator's wristwatch with two crowns. Four-body, polished, revolving bezel with blue and black enameled 15 degree graduation, graduated band, the second crown activates the revolving central dial, hinged back. Hinged steel cuvette. White enamel with painted radial Roman numerals for the 12-hour indication, the 180 degrees in upright blue Arabic numerals, central revolving matte silver dial with painted black radial Arabic numerals for the 60 minutes and painted red radial Arabic numerals for the 15 degrees, outer minute track. Blued steel Breguet hands. Cal. 37.9, rhodium plated, 17 jewels, straight-line lever escapement, monometallic balance, steel Breguet balance-spring, index regulator. Dial, case and movement signed. Diam. 48 mm. Thickness 15 mm. Notes The hour angle system was invented by Philippe Vanhorn Weems of the Annapolis Naval Academy, who trained Charles A. Lindbergh. The large ball-shaped winding-crown enables the watch to be wound by a pilot wearing gloves. It is practically impossible to build a commercial timepiece which will keep time to the exact second in a ship or an airplane. The inevitable variation from true time necessitated an extra calculation in navigation to compensate for this c Read more…