Omega Ref. 743.20 Pocket Chronometer
Record status
Individual type · partial
Period
circa 1905-1908
Maker / issuer
OmegaThis open-face, keyless-winding pocket chronometer is housed in an 18K yellow gold case. The watch features a white enamel dial with Arabic numerals and subsidiary seconds at 6 o'clock.
It is powered by a 20''' nickel-plated movement designated as Grade DDR, which includes 23 jewels, a going barrel with safety pinion, and a Guillaume balance. The mechanism is equipped with a straight-line lever escapement, diamond end-stone, and a swan-neck index regulator. The piece was adjusted by precision timer Werner A. Dubois in Bienne. This specific calibre was produced for official chronometric use, intended for astronomical observatory testing.
The watch is accompanied by documentation indicating it received a First Class Bulletin de marche from the Astronomical Observatory of Neuchâtel for the years 1911, 1912, and 1913, reflecting its performance in rigorous timing competitions that assessed movements in five positions and under varying temperature conditions.
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
- Pocket chronometer
- Maker
- Omega
- Adjuster
- Werner A. Dubois
- Reference
- 743.20
- Case material
- 18K yellow gold
- Place recorded
- Switzerland
- Movement number
- 2 362 051
- Movement caliber
- 20''' DDR
- Maker / attribution
- Omega
- Observatory certification
- Neuchâtel Observatory
Design
- Visible features
- • White enamel dial with Arabic numerals • Movement bridges engraved 'Chronomètre DDR' • Case back features commemorative engraving including 'GRAND PRIX PARIS 1900' • Swan-neck regulator visible on movement balance bridge
- Movement and Escapement
- The internal mechanism is a 20''' nickel-plated movement identified as Grade DDR. This grade, introduced in 1905, was designed specifically for official chronometer use in observatories. It incorporates 23 jewels, including two diamond end-stones, and features a going barrel with a safety pinion. Precision regulation is managed by a swan-neck spring and an eccentric snail device. The movement utilizes a Guillaume balance, which is a compensated bimetallic balance constructed from anibal and brass to minimize middle-temperature errors. The movement was adjusted by the professional precision timer Werner A. Dubois.
- Case and Dial Construction
- The watch features an open-face, keyless-winding construction crafted from 18K yellow gold. The round-shaped case houses a white enamel dial, which displays suspended Arabic numerals and a subsidiary seconds dial positioned at 6 o'clock. The case back is polished and bears detailed decorative engravings. The external decoration includes commemorative imagery celebrating the Grand Prix at the 1900 Paris exhibition. The overall physical condition is reported as good, though the auction description notes slight scratches on the case and hairlines on the enamel dial.
- Chronometric Performance and History
- This watch served as a high-precision instrument intended for use in formal observatory timing tests. Such tests were conducted over forty-five days, assessing movements across five positions and two distinct temperature ranges. These environments served as competition grounds for Swiss watch manufacturers. The subject piece received First Class Bulletins de marche from the Astronomical Observatory of Neuchâtel for three consecutive years between 1911 and 1913. These certifications corroborate its performance during the era of competitive chronometry.
Identification
- Reference
- 743.20
- Serial number
- 5 171 418
- 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: Specific production year within the 1905-1908 range is inferred
- Research required: Weight is provided as an approximate measurement