Heuer - Bund Sternzeit Reguliert Ref. 1551SGSZ Full Set

This Heuer Bundeswehr “Sternzeit Reguliert” ref. 1551SGSZ is one of the rarest military chronographs and in this excellent fulls set condition, a true holy grail. What sets it apart is not only its sidereal (star time) regulation — indicated by the wording “Sternzeit Reguliert” on the dial — but also its complete original setup.

Few chronographs survive with their full complement of period-issue accessories:

its original leather pouch stamped with Bundeswehr NSN 6675-12-308-6782,

• the original supply sheet (ANLBLAAN)
• the Astronomical Yearbook 1995 issued by the military geoscience office
• the original instructions booklet
• the book for astronomical direction and location, 1969 military issue
• star-finder booklets
• a slide rule
• star finder wheel
• special sky-gazing glasses with their original military box (NSN 846512-127-2258).

This chronograph was designed use by the artillery, rather than conventional timing. Unlike standard military chronographs that measured elapsed intervals in civil (solar) time, the Sternzeit variant was regulated to sidereal time—a system based on the rotation of the Earth relative to the stars, rather than the Sun. This made it useful for ballistic calibration. In practice, it was used by artillery officers and engineers of the Bundeswehr’s Geophysical and Artillery Corps to determine true north, launch angles, and azimuthal coordinates, often in combination with a theodolite, a star finder, and astronomical yearbooks. By aligning time readings with stellar positions, operators could obtain precise angular corrections for targeting and mapping. In essence, the “Sternzeit Reguliert” chronograph served as a portable sidereal reference clock, integrating watchmaking precision into the exact science of military geodesy and long-range artillery control—one of the rare instances where horology directly intersected with astronomy and defense technology.

Needless to say, the Sternzeit Reguliert chronograph required specialised training to operate effectively. Its use was limited to a small number of artillery officers and military surveyors trained in sidereal time calculations and celestial navigation techniques. With the rapid development of satellite-based ballistic systems this highly specialised instrument quickly became obsolete. Because of its narrow field of application and the complexity of its operation, production numbers were extremely low — its estimate that only around 100 to 150 chronographs were ever manufactured. This limited issue, combined with its technical specificity and historical context, makes the Heuer Bund Sternzeit Reguliert one of the rarest and most collectible military chronographs.

The stainless-steel, clamshell case measures 42 mm , excluding the original crown. It shows only minimal wear; the case halves clamp securely, and have correct Bundeswehr engravings and serial numbers between the lugs and on the back, NSN 6645-12-148-2298. The two directional turning bezel is in an excellent condition showing only very light traces of use Notice this is a different NSN from that found on “normal” Heuer Bund chronographs The original plexiglass is in an excellent condition.

The original black dial with bold Arabic numerals, luminous hands, and the hallmark inscription “Sternzeit Reguliert” is in an excellent condition, it shows only a delicate patina. The original luminous material has aged evenly. Under the hood lies the Valjoux 230 flyback calibre — a manual-wind flyback movement that allowed resetting and restarting the chronograph with a single push, essential in tactical timing operations. The Valjoux 230 is a trusted workhorse in military chronographs with a robust, serviceable construction.

The “Sternzeit Reguliert” version was adjusted not to civil time but to sidereal time — each sidereal day lasting 23h 56m 4s — to coordinate with astronomical calculations used in artillery surveys and theodolite angle determination. (We can either regulate this chronograph to sideral time or to solar time) The original Bund strap, (NSN 6645-12-145-6415) is complete with its original clasp and is in an excellent condition. The kit of accessories adds significant context: the celestial maps, instructions, astronomical yearbook, and other documents reflect the integrated role this instrument played in military surveying and rocket alignment. This Heuer Bund has been serviced in-house and prepared for reliable operation. It is delivered with our six-month guarantee and a certificate of originality. For a collector seeking a watch that marries mechanical complexity, historical purpose, and exceptional collectability, this Sternzeit Reguliert Bund is among the most compelling pieces in the military chronograph domain.

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