Omega
Speedmaster Professional
310.30.42 · 42mm · 50m
NASA-qualified manual chrono, 42mm hesalite Moonwatch.
Two chronographs from the same era, two opposite movement architectures
The Speedmaster Professional launched in 1957 with the column-wheel Cal. 321. NASA qualified the 105.003 in 1965 and Buzz Aldrin wore one on the lunar surface in 1969. Today's ref. 310.30.42 runs the cam-switch Cal. 3861: simpler architecture, same 42mm hesalite spec.
Zenith's Chronomaster Original 38 revives the 1969 A386, the watch that introduced the 36,000 vph automatic El Primero. The current 03.3200.3600 ships in a 38mm modern case with the new El Primero 3600, which adds a 1/10-second indication on the central seconds.
Spec sheet
| Attribute | Omega Speedmaster Professional | Zenith Chronomaster Original 38 |
|---|---|---|
| Reference | 310.30.42 | 03.3200.3600 |
| Case diameter | 42mm × 13.2mm | 38mm × 12.6mm |
| Bezel | Aluminium tachymeter | Black tachymeter ceramic-coated |
| Crystal | Hesalite (plastic) standard | Sapphire (box-style) |
| Movement | Cal. 3861 (in-house) | El Primero 3600 (in-house) |
| Architecture | Cam-switching, manual-wind | Column wheel + lateral clutch, automatic |
| Beat rate | 21,600 vph (3 Hz) | 36,000 vph (5 Hz) |
| Reserve | 50 hours | 60 hours |
| Antimagnetic | 15,000 gauss (Master Chrono) | Standard |
| Water resistance | 50m | 50m |
| Retail price | ~€7,400 | ~€8,400 |
Manual-wind vs automatic
The Speedmaster runs manual-wind by NASA spec preservation: Buzz Aldrin's wrist had no rotor, so today's wrist doesn't either. Wind 30-40 turns each morning. The Chronomaster is automatic with the El Primero 3600's rotor: never wind, just wear. Different rituals; different daily relationships.
Cam-switching vs column-wheel
Speedmaster Cal. 3861 uses cam-switching for the chronograph (mechanically simpler, NASA-spec preserved, slightly tactile pusher feel). Chronomaster El Primero 3600 uses column-wheel + lateral clutch (the haute-horlogerie standard, smoother engagement). Architecture is one of the most-debated chronograph topics in modern watchmaking.
Hesalite vs sapphire box crystal
The Speedmaster ships in two crystal options: hesalite (plastic, NASA-spec, lighter, scratchable but shatter-proof) at €7,400 or sapphire-sandwich at ~€8,000. The Chronomaster ships only with a box-style sapphire crystal that mimics the rounded acrylic of the 1969 A386. The hesalite Speedmaster has the most-vintage feel; the box sapphire matches it in look while staying scratch-proof.
Pros and cons
Speedmaster Professional · Pros
- NASA-qualified, lunar surface heritage
- Master Chronometer (15,000-gauss antimagnetic)
- Available with hesalite for vintage feel
- Manual-wind preserves Apollo-era ritual
Speedmaster Professional · Cons
- 42mm wears bigger than its number suggests
- Manual-wind requires daily attention
- 21,600 vph (3 Hz) lower than the El Primero
- 50h reserve vs the Chronomaster's 60h
Chronomaster Original 38 · Pros
- 38mm vintage proportion (smallest sweet spot)
- 36,000 vph (5 Hz) high-beat El Primero 3600
- 1/10-second indication on central seconds
- Box-style sapphire crystal matches A386 silhouette
Chronomaster Original 38 · Cons
- No equivalent space heritage
- Higher retail at €8,400
- Tri-coloured registers won't suit all dressier looks
Verdict: which one?
If you want the most-iconic chronograph in horology: Speedmaster Pro. NASA, Apollo, manual-wind, hesalite. The watch.
If you want a technically-superior 38mm chronograph that wears smaller: Chronomaster Original 38. 5 Hz, 1/10-second, automatic, box sapphire.
Buy on which heritage matters more (NASA vs El Primero), and on whether 38mm or 42mm fits your wrist. The €1,000 retail-price gap is rounding error at this tier.
Common questions
Speedmaster Pro or Zenith Chronomaster Original 38: which should I buy?
Buy on which heritage matters and which size fits. The Speedmaster Pro (~€7,400) is the NASA Apollo watch, manual-wind, 42mm, available with the vintage-feel hesalite crystal. The Chronomaster Original 38 (~€8,400) revives Zenith 1969 A386 - the first automatic high-beat El Primero - in a smaller 38mm case with a box sapphire crystal, an automatic movement and a 1/10-second readout. The €1,000 difference is rounding error at this tier.
Is the Zenith automatic and the Speedmaster manual?
Yes. The Speedmaster Pro keeps its hand-wound cam-switching Cal. 3861 to preserve the NASA flight spec - wind it daily. The Chronomaster Original 38 runs the automatic El Primero 3600 with a column-wheel and lateral clutch, so it just needs wearing, and it adds a 1/10-second indication on the central seconds thanks to its 36,000 vph beat. The Speedmaster runs at 21,600 vph.
Which wears smaller?
The Chronomaster Original 38 at 38mm x 12.6mm - it is the vintage-correct size for the 1969 A386 silhouette. The Speedmaster Pro at 42mm x 13.2mm wears bigger than its number suggests because of the lug shape and the busy dial.
Hesalite or sapphire: which crystal?
The Speedmaster comes both ways: hesalite (acrylic, NASA-spec, the most vintage feel, scratches but polishes out) at ~€7,400, or a sapphire sandwich at about €8,000. The Chronomaster Original 38 comes only with a box-style sapphire crystal that mimics the rounded acrylic of the original A386 - vintage look, scratch-proof.
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