Short answer
This phrase gets typed by people chasing two watches at once. Rendez-Vous is a Jaeger-LeCoultre collection, and part of that line carries a moon phase. Back of the moon points to the far side of the Moon, which Omega laser-ablated onto the caseback and movement bridges of the Speedmaster Dark Side of the Moon Apollo 8. So the search usually means a replica of a moon phase dress watch, or a replica of a moon-themed Speedmaster, and the buyer wants to know how the moon display and the caseback should behave before money changes hands.
Both checks reduce to one question: does the watch actually do what the dial and the back claim it does?
Why the moon phase is the weak point on a copy
A genuine moon phase is slow. A disc carrying two painted moons turns once every 29.5 days, close to the length of a lunar month. On a real one you can watch it for three days and see almost no movement.
Cheap copies skip the mechanism. They fit a 24-hour day/night disc instead: one moon, one sun, a full rotation every day. In a product photo it reads as correct. Worn for a week, it is obvious.
Test it without opening the case
- Photograph the moon position, wait 24 hours, photograph it again. A clearly different position means a day/night disc.
- Find the corrector. A real moon phase has its own pusher or recessed corrector, separate from the date.
- Study the aperture. Two crisp moons on a deep blue or aventurine disc is a good sign. Wobbly paint and a plastic sheen are not.
Precision is the next layer. A plain 59-tooth moon disc loses about a day every few years. Fancier gear trains stretch that to a single correction in a century or more. No replica reaches the second figure, and plenty miss the first.
The caseback: what the far side should show
On the Omega Apollo 8, the back is the whole point. The far side of the Moon is laser-ablated into the caseback, and the same treatment runs across the movement bridges so the watch reads as one piece of lunar surface. Reproductions tend to go soft right there. Crater detail smears, the tone flattens, and the engraving has no depth.
What I look at first:
- Depth. Genuine laser work catches light at an angle. Printed or stamped copies look flat from every angle.
- Text placement. Reference numbers, hallmarks and the Swiss Made mark sit on specific arcs. On copies they drift, crowd the edge, or use the wrong letter weight.
- Glass. Sapphire with coating on both faces throws a faint blue or purple tint at an angle. Mineral glass looks dull and scratches fast.
- Threads and gasket. A back that grinds going on, or seats with a visible gap, tells you the case was not machined to spec.
Movement clues
The 2018 Apollo 8 is hand-wound, so there is no rotor when you look through the back. A seller showing a spinning weight on that reference is showing you a different watch. Earlier Dark Side of the Moon models use an automatic chronograph with one subdial layout; a copy built on a generic chronograph often shifts those subdials, and the change is visible from across a table.
Pusher feel matters just as much. Real chronograph pushers have a short, clean travel and a crisp return. Mushy or long-travel pushers usually point to a cheap cam and lever stack.
On the Jaeger-LeCoultre side, the Rendez-Vous Moon is a small dress watch, so a seller offering one case size for every reference is guessing. Look for a signed rotor, perlage or Côtes de Genève finishing under the balance, and jewels set flush rather than glued in.
Questions to send before you pay
- A live video with today's date visible, moon phase in frame, caseback in focus.
- A clip of the moon phase being set through its corrector.
- The watch on a scale, plus a caliper reading of case diameter and thickness.
- Macro shots of the dial text, caseback engraving and clasp.
- Confirmation that the photos show the actual unit, not a stock image.
If the answers come back as catalog photos and a promise, walk. If they come back as a shaky phone video of the exact watch, you have something to judge.
Price versus what you get
At the bottom of the market the moon phase is a sticker. Mid-range money buys a working 29.5-day disc, decent printing and a case that survives daily wear. The top of the replica market gets closer on dimensions, sapphire, ceramic finishing and engraving, but the movement, the certification and the resale value stay out of reach. Know which tier you are shopping in before you compare prices.