Longines Lindbergh Hour Angle Watch

Sirike

2 months ago

The Longines Lindbergh Hour Angle Watch for today.

This 47.5mm wide, 16.3mm thick watch has a lug to lug distance of 58.20mm and a span between the lugs of 25mm. Coupled with a massive 9.2mm onion style crown, this watch is not for the faint of heart or those with slender wrists. It's water resistant to 30 meters.

This timepiece was made to Charles Limbaugh's specifications, in collaboration with Lt. Commander Philip Van Horn Weems, whom he met aboard the USS Langley after his first transatlantic flight. It was designed to use hour angle calculations to determine longitude. It's based on basic math; the Earth once every 24 hours, since a circle is 360°, every hour represents 15°. If you know the correct time where you are, all you need to know is the Zulu (Greenwish) hour angle of a celestial body to figure longitude. For that you need an Air Almanac and a sextant. To be accurate, the local solar time needs to be known so the Equation of time for the day would need to be added or subtracted. So the functions of this watch includes hours, minutes, seconds, internal rotating silvered dial for synchronization of the seconds hand with a radio time signal and rotating bezel to adjust to daily variations of the equation of time.

The dial is a white lacquered polished finish, with painted Arabic and Roman Numerals and heat blued steel hands.

The movement is the Longines L699.2, a behemoth at 36.6mm, is based on the ETA A07.111 and is only uses in this series (Weems and Limbaugh). It beats at 4Hz and has a 46 hour power reserve. A hunter style caseback opens up to show this beast of a movement in all it's glory and has an inscription on the inside of the caseback. This 2006 example is running +1/1 in 6 position after a complete service a few month ago. Fitted with a brand new OEM Alligator strap, it wears surprisingly well.

#longines #hourangle #pilot