Paul Ditisheim Astronomical Precision Pocket Watch No. 13784

Technical characteristics

Type

Calendar & astronomical watch

Jewel count

21 jewels

Case diameter

61mm

Case material

18ct yellow gold

Place recorded

Switzerland

Maker / attribution

Paul Ditisheim

Movement specification

21''' frosted gilded three-quarter plate

Hairspring specification

Palladium hairspring with Philips terminal curve

Design

Visible features

• Openface pocket watch with white enamel dial and subsidiary dials at 12, 3, 6, and 9 o'clock • Blued steel Breguet hands paired with a slender gold sun-tipped equation hand pointing near 12 o'clock • Outer perimeter inscribed 'TEMPS MOYEN À MIDI VRAI' and 'MÉRIDIEN DE PARIS' with 'PAUL DITISHEIM LA CHAUX DE FONDS' at 6 o'clock • Yellow gold case with top winding crown, bow, and lateral olivette pushers along the reeded band

Case Construction and Exterior Markings

The watch is housed in an 18ct yellow gold Empire case measuring 61 mm in diameter, featuring a deeply reeded band flanked by olivette adjustment pushers. The openface case incorporates a pendant winding crown and bow at the top, consistent with visible observations. According to auction cataloguing, the exterior case back displays sunburst engine-turning radiating from an oval cartouche bearing a 'J.F.' monogram. The interior case components carry multiple official stamps, including the Swiss Helvetia head assay mark, Crown assay, and French owl import marks on the bow, pendant, and interior rim, alongside Paul Ditisheim's 'PD' maker's punch mark and serial number 13784.

Reported Movement and Rating Credentials

The internal mechanism is not visible in the primary dial photograph; details are provided solely by the cataloguer's technical report. It is recorded as a 21''' frosted gilded three-quarter plate movement operating with a straight-line lever escapement and 21 jewels. The regulation assembly reportedly consists of a bi-metallic compensation balance with gold and platinum screws, an index regulator, and a palladium hairspring formed with a Philips terminal curve. The watch incorporates chronometric observatory credentials recorded on both the mechanism and cuvette. The movement back plate is engraved 'Bulletin de 1ère Classe de l’Observatoire, no. 13784', while the gold cuvette details its origin and accolades, citing 'Bulletin de 1ère Classe de l’Observatoire de Neuchâtel, Fabrique par Paul Ditisheim à La Chaux de Fonds, Grand Prix Exposition Universelle Paris 1900'. Accompaniments documented by the source include a copy of the Neuchâtel Observatory Chronometer Certificate and a fitted presentation box marked for Parisian retailer Idrac-Leroy.

Dial Display and Astronomical Indications

The white enamel dial is reported by the source as a 9-piece construction, displaying Arabic numerals and four distinct subsidiary registers at 12, 3, 6, and 9 o'clock. Blued steel Breguet hands indicate standard time, accompanied by a slender gold sun-tipped hand pointing to an equation of time sector calibrated along the upper minute track. The dial displays extensive astronomical and calendar information calculated specifically for the Paris meridian. The 12 o'clock register tracks months across a four-year leap-year cycle, while the registers at 9 and 3 o'clock display day and date alongside sunrise ('lever') and sunset ('coucher') times. A combined subsidiary seconds dial and moon-phase aperture sits at 6 o'clock, bordered by the signatures 'PAUL DITISHEIM LA CHAUX DE FONDS' and perimeter inscriptions 'TEMPS MOYEN À MIDI VRAI' and 'MÉRIDIEN DE PARIS'.

Identification

Serial number

13784

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.