Calibre 861 — the Moonwatch everyone knows

In one line

The chronograph Omega put in the Speedmaster in 1968 so it could build them faster. Twenty-eight years in the catalogue, flights on Skylab and the Shuttle, and never once on the lunar surface: by the time it arrived, Apollo was already flying the 321.

First things first: the 861 and the 1861 share a reference

The 3570.50 is always described as “the 1861 Speedmaster”. That is not always true, and the exception is not rare: Omega did not throw away the 861s left in the stockroom. It fitted them.

Telling them apart is a matter of colour, not of counting jewels: the 861 is gold-plated, the 1861 rhodium-plated and silver-grey. Through a display back you see it in two seconds. Behind the solid caseback of the classic Moonwatch you have to open the watch, so ask for photographs of the movement before you pay.

And beware the eighteenth-jewel argument, which gets misused constantly. The 861 has carried it since 1993. A late 861 and an 1861 have the same count.

861 against 1861: what actually changed

Very little. Which is precisely the argument for buying the cheaper one.

The 1861 does not correct a fault in the 861. It corrects an electroplating bath.

If the colour of bridges you will never see means nothing to you — the classic Moonwatch has a solid back — the 861 does exactly the same job for less money.

The 1968 handover

Same father as the one before. Albert Piguet signed off the 861 at Lemania, just as he had the 321, and it starts from the Lemania 1873 ébauche. What changed was the control: out went the column wheel, in came a cam. Fewer parts, quicker assembly, lower cost. The beat went up too, from 18,000 to 21,600 vibrations per hour. That was exactly what Omega needed, because by 1968 the Speedmaster had stopped being a niche chronograph.

The detail almost nobody mentions comes down to dates. The 861 appeared in 1968 in the reference 145.022, and Apollo 11 launched in July 1969: there was simply no time to put the new reference through NASA's qualification process. The agency carried on issuing the 105.012s and 145.012s it already held, every one of them on the calibre 321. No 861 ever walked on the Moon. It did fly, mind: Ron Evans wore a 145.022-69 in the command module on Apollo 17 while Cernan and Schmitt were down there in the dust. Skylab, Apollo-Soyuz and the first Shuttle flights followed.

It ran from 1968 to 1996 almost untouched. Seventeen jewels until 1992, eighteen from 1993. In 1996 Omega swapped the gold plating for rhodium, renumbered it 1861 and carried on as though nothing had happened. The architecture has never stopped: the 3861 Omega sells today is this same movement with a co-axial escapement on top. More than fifty years on one set of drawings.

Why it matters

This is the Speedmaster people grew up with: mechanically dependable, easy to find parts for, and far cheaper than an original 321 — the natural way in for anyone who wants a real Moonwatch.

Three things almost nobody knows

• The 861 that came closest to the Moon stayed in orbit Ron Evans, command module pilot on Apollo 17, wore a 145.022-69 while his two crewmates worked the surface on calibre 321s. That is as far as this movement ever got: twelve kilometres above the lunar ground, and not a step nearer.
• The plastic brake started here Somewhere around serial number 32,800,000, in 1970 or 1971, Omega replaced the two-piece steel brake with a single-piece one in Delrin, a DuPont polymer. It wears the fine teeth of the chronograph wheel far less. The earliest 861s still have the steel version, and some sources put the change nearer 1973.
• There was a GMT version almost nobody remembers The Flightmaster's calibres 910 and 911 are this same movement with a 24-hour hand. References 145.013, 145.026 and 145.036, between 1969 and 1976. Omega has never made anything like it since.

Technical data

What a watchmaker checks before buying one

Start with the brake. It is the part that holds the chronograph wheel when you stop. Run it, stop it, and watch the centre hand: if it jerks or shifts a hair as it halts, the brake is worn. It is a cheap part to change. Better to know that before you pay than after.

Second, the colour. A gilt 861 with a rhodium part inside — or the other way round — means somebody fitted whatever came to hand. Mechanically it may run perfectly. What it tells you is how the watch has been looked after.

And the good news, the thing that separates this calibre from the 321: parts exist. Omega built the 861 for twenty-eight years and its derivatives for twenty-five more. Servicing an 861 costs what a service costs. Servicing a 321 costs whatever the one watchmaker in your town who has the part decides to charge.

Watches that used it

• Speedmaster Professional ST 145.022 — 1968-1981, with the -68, -69, -71, -74 and -78 suffixes
• Speedmaster Professional 145.0022 (strap) and 345.0022 (bracelet) — from 1983
• Speedmaster Professional 3590.50 — 1988-1996, the last reference to carry the 861 as standard
• Speedmaster Professional 3570.50 — the earliest examples only, 1996-1998
• Speedmaster Mark II ST 145.014 — 1969-1973
• Flightmaster 145.013, 145.026 and 145.036 — with the GMT derivatives, calibres 910 and 911

The one that came before is the calibre 321, with its column wheel, in the Moon landing references.