Short Answer
A "Rendez-Vous Moonphase 240" is the listing name sellers use for their copy of the Jaeger-LeCoultre Rendez-Vous Moon Phase, a 36 mm dress watch with an automatic movement and a moon disc at 12 o'clock. The one test that matters is the disc: it must move one step per day and finish a full cycle in about 29.5 days. If the aperture swaps between a moon and a star every 24 hours, you are looking at a day/night indicator, not a moon phase. Every other check on this page is detail work, but that detail work is what separates a top copy from a cheap one.
Prerequisites
- A digital caliper that reads to 0.1 mm.
- A 10x loupe and a phone with a macro lens.
- Photos of the reference taken straight on, at an angle, and of the caseback.
- A timegrapher, or a watchmaker who will run one for you.
How to Inspect One, Step by Step
- Measure the case across the bezel from 3 to 9 o'clock, crown excluded. The Moon Phase sits at 36 mm; a 34 mm or 38 mm reading means the seller shipped a different model.
- Measure the gap between the lugs. A mismatch against the reference points to a generic case instead of a case cut for this model.
- Set the moon disc to a date you can confirm on a current lunar calendar, then check it again the next day. One single advance is correct. Two jumps, or a disc that never moves, is not.
- Look at the disc under the loupe. The moon should be a raised metal form with polished and brushed surfaces on a painted night sky. Flat foil stickers and printed moons are the usual shortcut.
- Turn the crown through every position. Winding, date or moon setting, and hand setting should each feel distinct, with no slip and no grind.
- Set the hands to 12 and check hour, minute and seconds alignment. Hand height above the dial is a second tell; hands set too low scrape the applied numerals.
- Read the dial under the loupe. Signature weight, numeral edges and the text at 6 o'clock should be crisp, with no halo or double edge from pad printing.
- Run the watch on a timegrapher for a full minute. Note the beat rate, amplitude and beat error, then compare that rate against the movement the seller claims.
- Flip the caseback and check engraving depth, rotor finishing and the calibre marking. Laser etching looks grey and shallow next to cut engraving.
Moon Disc vs Day/Night Disc
A true moon phase is driven by a wheel with 59 teeth, so the disc advances one position per day and needs a correction roughly every two and a half years. Cheap builds reuse a 24-hour wheel from a day/night complication, which is why the aperture shows a sun, a star or a second moon face. Ask the seller for a clip that spans two days of movement, or set the disc yourself and photograph it on consecutive mornings.
Movement Checks
Mid-tier copies run a Miyota 9015 or a Seagull automatic with a moon module added on top. Top copies try to mirror the calibre inside the original, which beats at 28,800 vibrations per hour. A watch that ticks, or one that runs at 21,600, is not the movement named in the listing. Ask for a photo of the movement with the rotor held still so you can read the bridge markings.
Common Giveaways
- A moon disc that flips once every 24 hours.
- Case diameter off by 2 mm or more.
- A printed signature that fuzzes under a loupe.
- A strap thinner at the lugs than the case cut.
- A deployant clasp with stamped, not cut, branding.
- A crystal that shows a purple or green cast at an angle.
- Caseback engraving that is shallow, grey and badly spaced.
Strap and Sizing
The 36 mm case wears larger than the number suggests because the bezel is thin and the lugs curve down, so on a 6.25 inch wrist it sits like a 38 mm watch. The original ships on alligator with a pin or folding buckle, and most copies arrive on stamped leather that you will swap out. Measure the lug gap before you order a replacement, since replica cases often accept 16 mm or 17 mm straps on lugs cut to look like 18 mm.
What to Expect at Each Tier
Entry copies get the diameter close and nothing else. Mid-tier copies fix the dial printing and the strap but keep the cheaper moon wheel. The best copies match the case profile, the dial texture and the disc cycle, and they cost several times more. Price bands shift between sellers, so treat a video of the disc advancing as the proof, not the asking price.