Longines L'Heure de l'Observatoire Deck Chronometer
Record status
Individual type · partial
Period
circa 1935
Maker / issuer
LonginesThis Longines L'Heure de l'Observatoire is a deck chronometer dating to circa 1935. It features a split-seconds chronograph and a 36-hour power reserve indicator.
The timepiece is notable for its specialized mechanism, which includes a revolving disc on the outer dial that allows for time synchronization to within a fraction of a second against an external signal. The watch is housed in an aluminium case with a reeded bezel and is mounted within a mahogany presentation box featuring an interior plaque describing its function. It is powered by the rhodium-plated Calibre 2129 movement, which incorporates 26 jewels, a monometallic balance, and a gold pallet fork.
The watch remains in good condition, as reported by the auction description, and is accompanied by its original mahogany box.
Evidence at a glance
- Linked sources
- 1
- Photograph views
- 1
- Catalogue references
- 0
Counts describe this entry’s documentation, not authenticity, rarity or completeness. Photographs may show one specimen; check each caption and licence.
Technical characteristics
- Type
- Deck chronometer with split-seconds chronograph
- Maker
- Longines
- Calibre
- 2129
- Functions
- Split seconds chronograph and power reserve
- Jewel Count
- 26
- Case Material
- Aluminium
- Dial Diameter
- 70 mm
- Box Dimensions
- 16 x 14 x 6 cm
- Place recorded
- Switzerland
- Maker / attribution
- Longines
Design
- Visible features
- • Reeded bezel on the aluminium watch case • Interior mahogany box plaque text • Power reserve sector on the dial • Visible split-seconds function
- Case and Dial Design
- The chronometer is housed in a two-body mahogany box with a hinged lid. The interior of the box features an inscribed plaque that reads 'Le Chronometre Longines Donne Exactement L'Heure de L'Observatoire'. The watch itself is contained within an aluminium case that features a reeded bezel and side-mounted buttons for controlling the chronograph functions. The brushed silver dial displays black Arabic numerals and a power reserve sector. A key feature is the outermost revolving chronograph ring, which is painted with blue second and fifth-of-a-second divisions alongside Arabic five-second numerals. The dial is equipped with blued steel spade hands to ensure legibility against the silver background.
- Documentation and Attribution
- This specific timepiece is attributed to Longines and is identified by the serial number 7513094, manufactured circa 1935. The object, dial, box, and movement are signed by the manufacturer. The chronometer is documented in literature regarding historical timing instruments. Specifically, it is described and illustrated in the 1948 publication 'L'Horlogerie - Une Tradition Helvétique' by Samuel Guye, within the chapter concerning onboard chronometers for automobiles and aircraft.
- Movement and Chronometer Mechanism
- The watch is powered by the rhodium-plated Calibre 2129, a movement featuring fausses côtes decoration. It utilizes a straight-line lever escapement with a gold pallet fork, a monometallic balance, and a blued steel Breguet balance spring fitted with a micrometric regulator. The construction of the aluminium case, balance, and pallet fork is noted for providing antimagnetic properties to the device. The split-seconds chronograph includes visible work. The watch provides a 36-hour power reserve and includes a special device to facilitate precise time synchronization. The user stops the split-seconds hand at an hour signal and adjusts the revolving chronograph ring so that the '60' division aligns with the hand, subsequently releasing it to synchronize the time to a fraction of a second.
Identification
- Serial number
- 7513094
- Source note
- Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.
Catalogue references
No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.
Research required
- Research required: Movement is stated to require an overhaul
- Research required: Revolving ring mechanism operation assumes active user interaction