Omega
Speedmaster Transitional - Tritium C-861 golded

Omega Speedmaster Professional 3590.50 (transitional 145.022 ST) -1992 pre-owned, gilt Caliber 861, “honey” tritium dial, Hesalite crystal, 42 mm steel

“Under the moon of missions and the light of everyday life, the tritium dial reveals the stages of its time spent in service.”

Some Speedmasters never chase the sterile perfection of eternal white; they gain nuance, like a silver-gelatin print warming with the years. The tritium no longer lights up the night; it lights up the watch’s history. In the frank light of a workshop morning or the softness of a café in Aix, the markers take on that honey tone that belongs only to this very watch, to its exact path: a traveler’s wrist, summers and shirts, slightly smoky rooms, winter skies. Wearing a 1992 Speedmaster tritium day in, day out is accepting that no photo ever fixes its color for good and that each hour renews the dialogue: sometimes amber, sometimes straw, sometimes almost caramel. It isn’t an effect; it’s a memory—the kind that turns an instrument of chronometry into a companion you choose every morning, for the touch of Hesalite, for the supple cadence of the Caliber 861, for that feeling that time really has passed here—and that it suits you.

Born in 1957, the Speedmaster entered the space epic in 1965 before becoming “Professional.” In 1968, reference 145.022 introduced Caliber 861 (replacing the 321) and set the modern architecture: 42 mm, lyre-lugs, Hesalite crystal, screwed solid case-back with hippocampus, and a tachymeter bezel. In the early 1990s, the external catalog shifted to 3590.50 for tritium versions while many case-backs still carried the ST 145.022 stamp. Our 1992 example belongs to this tritium transitional period (1990–1996) before the arrival of Caliber 1861 and modern lume.

The 42 mm steel case shows those crisp lyre-lugs with sharp edges and satin-polished bevels that catch the light beautifully. The domed Hesalite—soft to the eye and warm in photographs—carries the Ω emboss at center. The black tachymeter bezel frames a matte black dial with historic typography, signed T SWISS MADE T, where the tritium indices have taken on a highly desirable honey patina, in harmony with the original tritium baton hands. On the back, the solid case-back engraved with the hippocampus recalls the tool heritage. At its heart beats Caliber 861, a cam-switched chronograph that is robust and precise, 21,600 vph with about 48 hours of power reserve—a reliable regulation proven over decades of real-world use. Original water-resistance was not designed for today’s diving; as a vintage watch, it’s meant for daily life—light rain, city use, travel—after our standard workshop checks. From office to weekend, this 1992 145.022/3590.50 reads immediately as a professional chronograph in a balanced format; it moves from denim to jacket, from NATO to smooth leather, from tan grained to classic black. Its honey tritium patina softens the tool watch and adds that subtle note connoisseurs spot at first glance. You wear it to write, to drive, to think—unbothered by glare: Hesalite softens the scene, the bezel draws the measure, and your wrist smiles.

The Caliber 861 was born in 1968 to succeed the 321: it traded the column wheel for a cam-switch (shuttle cam) and raised the beat rate to 21,600 a/h with roughly 48 h of reserve. Simpler to produce, it kept the Lémania 1873 architecture, the foundation for all later variants (863, 1861, 1863). These choices explain its robustness and sensible service costs, which is why it powered the Speedmaster for nearly three decades. At the turn of the 1980s–1990s, Omega generalized a gilt-tone galvanic finish (gold/yellow-copper) on the bridges and mainplate of the 861. First seen on special series in the late 1980s, then standard on 3590.50 around 1990, it visually distinguishes the last 861s from earlier, more copper-rose executions. On a 145.022/3590.50 from 1992, you therefore find a perfectly period-correct gilt 861.

Technically, these late 861s also received a supplementary jewel update: the 861 moved from 17 jewels (through 1992) to 18 jewels (from 1993)—a discreet but telling refinement. Thus a 1992 example is 17-jewel, while 1993–1996 pieces are 18-jewel. The Delrin chronograph brake (engineering polymer)—introduced in the 1970s and retained by Omega for its friction behavior, stability and quietness—remains present on most late-production 861 and on their successor 1861 (the display-back 1863 uses a metal brake).

Across references, the transition reads as follows: 145.022 (becoming internal 145.0022) carries Caliber 861 from 1968 to the late 1980s; from 1988/1989, 3590.50 (still “Moonwatch” with plexi and solid back) keeps the gilt 861 until the switch to Caliber 1861 in 1996—a highly continuous evolution (rhodium finish instead of gilt, 18 jewels, same frequency and reserve). In short, the 1990s gilt “861” is the fully matured form of the 861: the same proven Lémania 1873 architecture, a brighter modern finish, refined regulation (18 jewels from 1993), and that signature Delrin brake. On a 1992 Speedmaster, you are looking for exactly that combination: gilt bridges, 17 jewels, 21,600 a/h—just before the aesthetic and plating shift to the rhodium-finished 1861 in 1996.

The tritium era of the Speedmaster Professional with 861 continues into the early 1990s under catalog code 3590.50 while many case-backs still read ST 145.022—exactly like this example, categorizing it as a Transitional model. In 1996, the family evolves to 3570.50 with Caliber 1861, and modern luminous compounds arrive at the end of the decade. Our 1992 watch sits at the heart of the tritium period most sought after by collectors. It shows a homogeneous honey tritium patina, original dial and hands in handsome condition, light signs of wear consistent with age, and a Hesalite crystal freshly and carefully polished by our workshop if needed. It comes with a Mostra travel pouch for safe carrying. Full inspection, timing, and running tests have been completed by the Mostra Atelier. Covered by our 3-year warranty.

At Mostra, Aix-en-Provence, we know the Speedmaster well. Every example is selected for historical and aesthetic coherence, opened and checked in-house by a certified watchmaker, then prepared for true daily use. Authenticity, regulation, amplitude, power reserve—nothing is left to chance. Your 3-year warranty, our concierge services (straps, advice, future overhauls), and the support of a specialized house turn a purchase into a long-term relationship. 

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