Omega Speedmaster Buying Guide: Moonwatch Hesalite vs Sapphire
This Omega Speedmaster buying guide covers the watch most people mean when they say "Speedmaster": the Speedmaster Professional Moonwatch. The short answer for most buyers is simple. The current Moonwatch is a 42 mm, hand-wound chronograph powered by the calibre 3861, and it comes in two main steel versions: a Hesalite (acrylic) crystal with a solid caseback, or a "sapphire sandwich" with sapphire on the front and back. Pick Hesalite if you want the version closest to the flight-qualified original, and sapphire if you want better scratch resistance and a view of the movement.
The rest of this guide explains the differences between the two crystals, how the current references compare with the previous calibre 1861 generation, and what to check before buying one pre-owned.
What is the Omega Speedmaster Professional Moonwatch?
The Speedmaster was introduced in 1957 as a sports and racing chronograph. NASA qualified it for crewed space missions in 1965, and it was worn on the Moon during Apollo 11 in 1969, which is where the "Moonwatch" name comes from. The modern Moonwatch keeps the core of that design: a black dial with three sub-dials, a tachymeter scale on the bezel, twisted "lyre" lugs and a manual-winding movement with no automatic rotor.
Omega makes many other Speedmaster models, including automatic chronographs, smaller sizes and racing-themed versions. This guide focuses on the Professional Moonwatch because it is the reference point for the whole line and the model buyers ask about most.
Hesalite vs sapphire: which Speedmaster crystal should you choose?
The crystal is the biggest decision when buying a Moonwatch, because it changes the look, the caseback and the movement finish you get.
Hesalite crystal
Hesalite is Omega's name for the acrylic crystal used on the flight-qualified Speedmaster. Acrylic was preferred for space use because it does not break into fine shards the way glass can. On the wrist it has a soft dome and a warm, slightly distorted look at the edges that many collectors prefer. The trade-off is that acrylic scratches easily. The good news is that light scratches can usually be polished out at home or during a service. Hesalite versions have a solid steel caseback, and on the current generation the dial uses a printed Omega logo.
Sapphire crystal ("sapphire sandwich")
The sapphire versions use a sapphire crystal on the front and a sapphire display caseback, which is why collectors call them the sapphire sandwich. Sapphire is far more resistant to everyday scratches and looks clearer and flatter. The display back lets you see the movement, and on the current generation the sapphire model also has an applied (raised) Omega logo on the dial and polished centre links on the bracelet. Sapphire versions typically cost more than their Hesalite equivalents, both new and pre-owned.
| Feature | Hesalite | Sapphire sandwich |
|---|---|---|
| Crystal material | Acrylic (Hesalite) | Sapphire |
| Scratch resistance | Low, but scratches can be polished out | High |
| Caseback | Solid steel | Sapphire display back |
| Dial logo (current calibre 3861 models) | Printed | Applied |
| Bracelet centre links (current models) | Brushed | Polished |
| Case thickness (current models) | About 13.6 mm | About 13.2 mm |
| Link to the flight-qualified watch | Closest to the original specification | A more modern, everyday option |
Current Speedmaster Moonwatch references (calibre 3861)
In January 2021 Omega updated the Moonwatch with the calibre 3861, a hand-wound Co-Axial chronograph certified as a Master Chronometer by METAS. That certification includes resistance to magnetic fields of up to 15,000 gauss. The movement runs at 21,600 vibrations per hour, has a power reserve of about 50 hours, and uses a silicon balance spring.
The 2021 update also refined the design. The dial gained a stepped outer section, the bezel brought back the "dot over ninety" detail found on early Speedmasters, and the bracelet was redesigned with smaller, more tapered links and a new clasp. The case stays at 42 mm with 50 metres of water resistance.
| Reference | Crystal | Caseback | Fitted with |
|---|---|---|---|
| 310.30.42.50.01.001 | Hesalite | Solid steel | Steel bracelet |
| 310.30.42.50.01.002 | Sapphire | Sapphire display | Steel bracelet |
| 310.32.42.50.01.001 | Hesalite | Solid steel | Strap |
| 310.32.42.50.01.002 | Sapphire | Sapphire display | Strap |
| 310.30.42.50.04.001 | Sapphire | Sapphire display | Steel bracelet, white lacquered dial |
Omega also makes the calibre 3861 Moonwatch in its own 18k gold alloys, Sedna gold and Canopus gold. These use the same movement but cost considerably more than steel.
Previous Speedmaster Moonwatch references (calibre 1861 and 1863)
Before 2021, the Moonwatch used the calibre 1861, a hand-wound chronograph descended from the calibre 861 that first appeared in the Speedmaster in 1968. From 1996, Omega offered two versions: a Hesalite model with a solid back and the calibre 1861, and a display-back model with the more decorated calibre 1863. These earlier watches are about 14 mm thick and are a popular way into the Moonwatch on the pre-owned market.
| Reference | Crystal | Caseback | Calibre |
|---|---|---|---|
| 3570.50 | Hesalite | Solid steel | 1861 |
| 3573.50 | Sapphire | Sapphire display | 1863 |
| 311.30.42.30.01.005 | Hesalite | Solid steel | 1861 |
| 311.30.42.30.01.006 | Sapphire | Sapphire display | 1863 |
The 311.30 references replaced the four-digit numbering around 2014, and both were produced until the calibre 3861 models arrived in 2021. Functionally the calibre 1861 and 1863 are the same; the 1863 simply has more decorative finishing because it is visible through the caseback.
Calibre 3861 vs calibre 1861: which generation to buy?
Choose a calibre 3861 Moonwatch if:
- You want the strongest magnetic resistance and Master Chronometer certification.
- You prefer the updated bracelet and the stepped dial with the dot over ninety.
- You want a slightly thinner case and a longer power reserve.
Choose a calibre 1861 or 1863 Moonwatch if:
- You want the movement family that powered the Moonwatch for decades.
- You are working to a tighter budget, since older references generally sell for less than current ones.
- You do not mind an older bracelet design and a slightly thicker case.
Neither choice is wrong. Both are 42 mm, both are hand-wound and both keep the classic Moonwatch look. The decision usually comes down to whether you value the newer movement and bracelet or the lower price of the older generation.
What to check when buying a pre-owned Speedmaster
- Match the movement to the reference. A Hesalite solid-back model should use the 1861 or 3861; a sapphire display-back model of the earlier generation should show the 1863. The Moonwatch Professional is hand-wound, so there should be no rotor.
- Check the crystal. Hesalite should have a visible dome. A perfectly flat, scratch-free crystal on a supposed Hesalite model points to either a sapphire version or a problem.
- Inspect the bezel. The tachymeter insert should be cleanly printed and sit flush. On current models, the dot over ninety should be round and centred.
- Look at the lugs and case. Heavy polishing can soften the sharp edges on the twisted lugs and bezel. Light wear is normal; rounded edges reduce appeal.
- Test the chronograph. The pushers should start, stop and reset the hands cleanly, with the hand returning exactly to zero.
- Ask about service history and paperwork. A recent service record, original box and warranty card add confidence and generally add value.
Every watch we sell is inspected and its authenticity guaranteed, so these checks are already done for you when you buy from Crescent Watch Guys.
Frequently asked questions
Is the Hesalite or sapphire Speedmaster better?
Neither is better in every way. Hesalite is closest to the flight-qualified original and scratches can be polished out, while sapphire resists scratches and adds a display caseback. Most buyers choose based on looks and how carefully they wear their watches.
What size is the Omega Speedmaster Moonwatch?
The Speedmaster Professional Moonwatch is 42 mm in diameter. Current calibre 3861 models are about 13.2 mm thick with sapphire and about 13.6 mm with Hesalite, slightly thinner than the earlier 1861 generation.
Is the Speedmaster Moonwatch automatic?
No. The Professional Moonwatch is hand-wound, which means you wind it through the crown. Omega makes automatic Speedmaster models, but they are separate lines with different movements.
Is the Omega Speedmaster waterproof?
The Moonwatch is water resistant to 50 metres, which covers rain, hand washing and splashes. It is a chronograph rather than a dive watch, so it is better to avoid swimming with it and never operate the pushers underwater.
What is the difference between the 311.30.42.30.01.005 and 310.30.42.50.01.001?
Both are steel Hesalite Moonwatches on a bracelet. The 311.30.42.30.01.005 uses the earlier calibre 1861, while the 310.30.42.50.01.001 uses the calibre 3861 with Master Chronometer certification, a stepped dial and the redesigned bracelet introduced in 2021.
Shop the Omega Speedmaster at Crescent Watch Guys
Browse our pre-owned Omega watches to see which Speedmaster models are in stock, or check new arrivals for the latest pieces. If you are looking for a specific reference, such as a sapphire sandwich or a calibre 1861 Hesalite, our team can help find it through our available to order service. Thinking about upgrading? You can sell or trade your watch toward a Moonwatch, and our watch repair team can help keep a Speedmaster running well. For more on the brand, read our guide to Omega Seamaster models collectors love.