Omega
Omega Speedmaster Professional Moonwatch
The verdict
A 42 mm hand-wound chronograph with a documented spaceflight history and, since 2021, a movement certified at 0 to plus 5 seconds a day. It is very good at being read, wound and repaired, and poor at water. Look elsewhere if you want an automatic, a date window, or a watch you can swim in.
On this page (9 sections)
Omega's Speedmaster Professional is a hand-wound chronograph in a 42 mm steel case, with three registers, a fixed tachymeter bezel and no date. It has been sold in that form since the 1960s. What changed in January 2021 was the movement and, in smaller ways, the case and bracelet around it. Everything below describes that current generation. Where the earlier caliber 1861 watch differs in a way that should change your decision, we say so.
The specification
| Item | Hesalite, ref 310.30.42.50.01.001 | Sapphire, ref 310.30.42.50.01.002 |
|---|---|---|
| Case diameter | 42 mm | 42 mm |
| Lug to lug | 47.50 mm | 47.50 mm |
| Thickness | 13.54 mm | 13.18 mm |
| Lug width | 20 mm | 20 mm |
| Crystal | Domed Hesalite acrylic with a central Omega logo | Domed sapphire, anti-reflective inside |
| Caseback | Solid steel, embossed seahorse | Sapphire display back |
| Water resistance | 5 bar (50 m) | 5 bar (50 m) |
| Movement | Omega 3861, in-house, hand wound, Co-Axial escapement, silicon balance spring, 26 jewels | |
| Beat rate | 21,600 vibrations per hour (3 Hz) | |
| Power reserve | 50 hours | |
| Published rate | 0 to plus 5 seconds a day, Master Chronometer certified by METAS | |
| Bracelet | Steel, five arched links per row, folding clasp with comfort adjustment | |
The NASA qualification, and what it covers
This is the most repeated claim in watch marketing, and the underlying history is better than the marketing version.
In 1964 the NASA Manned Spacecraft Center in Houston needed a wrist chronograph for crewed flight. Watches were bought anonymously from a Houston retailer so that no manufacturer could prepare a special sample, and chronographs from several makers went into a qualification program run by engineer James H. Ragan. The tests were environmental rather than horological: high temperature at 70 degrees Celsius for 48 hours followed by a short spell near 93 degrees, low temperature at minus 18 degrees, repeated temperature cycling in a vacuum chamber, humidity, a pure oxygen atmosphere, shock, acceleration, decompression, high pressure, vibration from 5 to 2,000 Hz, and 130 dB of acoustic noise. The Omega was the one that came out running. On 1 March 1965 NASA declared the Speedmaster flight qualified for all manned space missions.
Caliber 3861 against caliber 1861
Both descend from the Lemania 1873 of the late 1960s, and both are cam-actuated with a lateral clutch rather than column-wheel chronographs. The pusher feel is the same slightly mechanical click it has always been, and anyone telling you the 3861 is a new movement is overstating it. Our chronograph guide explains why cam and column wheel are a question of feel and cost rather than of accuracy, and what a chronograph is actually for covers the timing itself.
What genuinely changed is the regulating organ. The 3861 uses Omega's Co-Axial escapement, which reduces sliding friction at the point where energy is delivered to the balance, plus a silicon balance spring that is not ferromagnetic. That combination is what allows the finished watch to be tested at 15,000 gauss and still run, and it is why the sapphire version can have a display back without a soft iron shield. The watch then passes the eight-part Master Chronometer protocol administered by the Swiss federal metrology institute, which sets the rate window at 0 to plus 5 seconds a day on the cased watch. Our comparison of official standards against brand standards sets out how that differs from a plain chronometer certificate, and Rolex against Omega covers why the two houses picked different windows.
In practice a healthy 3861 tends to land in the low single digits fast, which suits a watch you wind every morning. A well-serviced 1861 is often perfectly good too, but nobody published a figure for it, so you are buying an individual watch rather than a specification.
How it wears
The important number is not 42 mm. It is 47.50 mm from lug tip to lug tip, which is compact for a 42 mm case, and the reason the Moonwatch sits happily on wrists that a modern 42 mm diver overhangs. The lugs are twisted and drop away sharply, and the case sides are narrow because the bezel does most of the visual work. Anything from about a 16 cm wrist, 6.3 inches, upward carries it without effort, and it is wearable well below that. Our size calculator and the lug to lug explainer cover why that measurement matters more than diameter.
Height is the honest complaint. At 13.18 to 13.54 mm on a flat, wide case, it is not a watch that slides under a fitted shirt cuff. The bracelet helps: the current five-arch-link design tapers properly and the clasp has a comfort adjustment you can operate without a tool, which is a real improvement on the older folded bracelet. On a 20 mm strap the watch loses several millimeters of perceived bulk, and our straps and bracelets guide covers the trade.
What it is good at
Legibility, first. White on matte black, no date window interrupting the dial, three registers that are actually readable, and a running seconds hand at nine that tells you the watch is alive. Second, serviceability: this architecture has been made continuously for over fifty years, every competent watchmaker knows it, and parts are not exotic. Third, it is a hand-wound watch, which means no rotor noise, a thinner movement than an automatic chronograph, and a daily ritual that some owners like and others find tiresome. Fourth, the design is settled. It is not going to be restyled out from under you.
What is wrong with it
The water resistance is the weak point and it is not close. Fifty meters at this price is poor, and it constrains how you can live with the watch. Do not operate the pushers wet, and have the case pressure tested when gaskets are replaced.
The hand winding is not optional. Fifty hours means that if you take it off on Friday evening it is stopped by Sunday afternoon, and resetting a chronograph is more fiddling than resetting a three-hander. There is no date at all, which is either the point of the watch or a daily irritation depending on you.
The Hesalite crystal divides people honestly. It scratches if you look at it wrong. It also polishes out in ten minutes with a mild abrasive, which sapphire never will, and our crystal comparison lays out the trade properly. Finally, the movement finishing on the Hesalite version is functional rather than decorative, which is invisible behind a solid caseback and is exactly why that version costs less.
What it costs, new and used
Figures below are indicative US dollars, quoted before sales tax, and they move. Outside the United States the local list varies with tax, import duty and how Omega distributes there. Treat them as orders of magnitude.
New, the Hesalite version on the steel bracelet has generally sat around $7,100, with the sapphire version roughly $900 above it, close to $8,000. On a strap, deduct a few hundred. Pre-owned examples of the 3861 generation typically trade below list, often in the $5,000 to $6,500 band depending on condition, completeness and market, and the older 1861 references sit lower again. The manual-wind Speedmaster has historically been one of the steadier Omega references on the secondary market, but that is a market condition and not a feature, and our guide to value and depreciation explains why nobody should buy it as a position.
Running cost is dominated by servicing. Over ten years, expect one overhaul at an indicative $800 to $1,200 at a brand service center, plus a crystal replacement if you have gone the sapphire route and scratched it. Our answer on service cost explains what drives the bill and the cost of ownership calculator will run a decade of it against your own numbers. Omega's warranty on Master Chronometer watches runs five years, which is longer than most of the industry.
The alternatives, and when each is the better answer
- Omega Seamaster Diver 300M. The same Master Chronometer standard, an automatic movement, a date, and 300 m of water resistance for less money. If you want one Omega and you swim, this is the more sensible watch and the Speedmaster is the more interesting one.
- Tudor Black Bay Fifty-Eight. About two thirds of the price, 70 hours of reserve, and far more robust. It is not a chronograph, which is either the whole objection or no objection at all.
- A Speedmaster with caliber 1861, pre-owned. A meaningful saving for the same look and the same architecture, at the cost of the certificate, the silicon balance spring and the newer bracelet. Read our pre-owned guide first, and budget for a service you may not have been told about.
- An automatic chronograph from a tier below. If the daily winding is the sticking point rather than the price, an automatic chronograph solves it, and our first-watch guide covers what to look for.
Who should buy one
Buy it if you want a chronograph you will actually read, if the winding ritual appeals rather than annoys, and if you are content with a watch that stays out of the shower. Do not buy it as your only watch if you swim or work wet, and do not buy it on the NASA story alone.
Choose the 3861 generation if you want the published rate figure and the newer bracelet. Choose an 1861 example used if you want the look for less and are comfortable judging an individual watch rather than a specification. Either way, have anything pre-owned pressure tested before it goes near water.
Common follow-up questions
Is the watch sold today the one NASA qualified?
No, and Omega does not claim otherwise in its technical documentation. The 1965 qualification applied to the watch as delivered then, reference ST 105.003, with a column-wheel caliber 321. The current watch shares the dial layout, the 42 mm case concept and the hand winding, but the movement, the bracelet and the case profile have all changed. The qualification is documented history attached to a 1960s object.
Hesalite or sapphire?
Hesalite is an acrylic crystal. It scratches easily and polishes out at home with a mild abrasive, it does not shatter, and it gives the dial a warmer look. Sapphire resists scratches and cannot be repolished, and the sapphire version adds a display back. Counter-intuitively the Hesalite watch is the thicker of the two, at 13.54 mm against 13.18 mm, because its dome is taller.
Can I swim with it?
Omega rates it to 5 bar. That covers rain, hand washing and an accidental soaking. It is not a swimming watch, and the pushers must never be operated in water. The gaskets are also the oldest part of the watch by design intent, so a 50 m rating on a fifteen-year-old Speedmaster that has never been pressure tested is a number on a caseback, not a promise.
How often does it need servicing?
Omega guidance for its mechanical watches sits in the five to eight year band. A chronograph costs more to overhaul than a time-and-date watch because there are more parts to strip, clean and adjust. Budget an indicative $800 to $1,200 at a brand service center in the United States, expect a different figure elsewhere because bench rates track local wages and local tax, and treat any interval as a guide rather than a deadline.
Sources and further reading
- OMEGA published specification pages for references 310.30.42.50.01.001 and 310.30.42.50.01.002, for diameter, lug to lug, thickness, lug width, crystal type, caseback, water resistance and caliber.
- OMEGA published documentation for caliber 3861, for the Co-Axial escapement, silicon balance spring, 21,600 vibrations per hour, 50 hour power reserve and 26 jewels.
- Swiss Federal Institute of Metrology (METAS), Master Chronometer certification criteria, for the eight tests, the 0 to plus 5 seconds a day window and the 15,000 gauss exposure.
- Contrôle Officiel Suisse des Chronomètres (COSC) published testing criteria, and ISO 3159 on wrist-chronometers, for the movement-level certification that precedes the METAS test.
- NASA Johnson Space Center Oral History Project, interview with James H. Ragan, the NASA engineer who ran the chronograph qualification program at the Manned Spacecraft Center.
- ISO 22810, Horology: Water-resistant watches, for what a 5 bar marking does and does not promise.
- OMEGA published warranty and service documentation, for the warranty term and the recommended service interval.
Last reviewed 4 September 2026. Spotted an error? Tell us and we will fix it in public.