The Speedmaster Moonwatch Professional comes in two main steel versions: one with a hesalite crystal and solid caseback, one with sapphire front and back, the "sapphire sandwich". Everything else is the same.
At a glance
| Hesalite (310.30.42.50.01.001) | Sapphire (310.30.42.50.01.002) | |
|---|---|---|
| Case | 42mm steel | 42mm steel |
| Front crystal | Hesalite (acrylic) | Sapphire |
| Caseback | Solid steel | Sapphire, shows the movement |
| Calibre | 3861, manual-winding | 3861, manual-winding |
| Certification | Master Chronometer | Master Chronometer |
| Water resistance | 50m | 50m |
A short history
The Speedmaster was introduced in 1957 and qualified by NASA for crewed space missions in 1965. It was on the wrist of astronauts during the Apollo moon landings, which is where the "Moonwatch" name comes from. Hesalite was part of that story: unlike glass, it doesn’t shatter into shards, which matters in a spacecraft.
Hesalite vs sapphire
Hesalite has a warmer, slightly domed look with a faint distortion at the edges that many collectors love, and scratches can be polished out. Sapphire is far more scratch-resistant and looks crisper, but it reflects more light and, if it’s ever damaged, needs replacing. The sapphire version also shows the movement through the caseback.
The calibre 3861
Both use the manual-winding calibre 3861 with Omega’s Co-Axial escapement, certified as a Master Chronometer by METAS, which includes strong resistance to magnetism. It keeps the classic manual-wind ritual of the original Moonwatch.
Buying checklist
- Crystal condition. Hesalite scratches can be polished; deep cracks need replacement.
- Chronograph. Start, stop and reset should be crisp, with the seconds hand returning to zero.
- Calibre. Make sure the watch has the 3861 if you’re buying the current generation.
- Box and papers. A full set adds confidence and value.
Which one to choose
Choose the hesalite if…
You want the version closest to the original Moonwatch, with its warmer look and story.
Choose the sapphire if…
You want maximum scratch resistance and to see the movement through the caseback.
FAQ
Is the hesalite version the "real" Moonwatch?
It’s the one closest to the flight-qualified watches; both are official Moonwatch Professional models.
Do I need to wind it?
Yes. The calibre 3861 is manual-winding: a few turns of the crown each day.
Is it waterproof?
It’s rated to 50 metres, fine for everyday wear and rain, not for diving.
Shopping for one of these? Every watch we sell is authenticated in Los Angeles, with insured delivery and video on request. Text us at (310) 363-0481.
