A fake Audemars Piguet Jules Audemars Moon Phase gives itself away at three points: the moon phase disc, the dial printing, and the case finishing. Check those three items before anything else. Authentic watches use a moon disc with a grained sky, stars cut to sharp points, and a moon in relief. Copies print the whole disc flat, so the stars blur at the edges and the moon looks like a decal.
Prerequisites
- A 10x jeweler's loupe and a bright, diffused light source
- The reference number engraved on the case back
- A caliper for case diameter and thickness
- The current lunar age from a moon phase calendar, so you can test the function
- Catalog photos of the same reference, placed side by side with the watch
Step-by-step inspection
- Read the reference number on the case back and match it to a Jules Audemars moon phase reference in the maker's catalog.
- Measure the case diameter and thickness with a caliper, then compare both numbers to the published specs for that reference.
- Set the moon phase to the current lunar age using the crown or corrector, then study the disc position under the loupe.
- Check the sky section of the disc for a grained texture, sharp star points, and a moon with visible relief.
- Tilt the watch toward the light and confirm the sky changes tone as the viewing angle moves.
- Inspect the brand signature under 12 o'clock and the Swiss Made mark at the bottom of the dial for crisp edges and correct spacing.
- Study the dial surface around the aperture for guilloche or opaline finishing, looking for tool marks or print that sits on top of the texture.
- Run a fingernail along the bezel edge and the case flanks to feel for an even bevel.
- Examine the case back engraving under the loupe for depth, font weight, and letter spacing against the catalog image.
- Inspect the crown for an engraved logo, correct tooth shape, and smooth winding.
- Photograph the movement through the display back, if one is fitted, and compare the finishing and engraving to known examples.
- Check the clasp engraving, strap stitching, and buckle weight against a confirmed authentic piece.
- Compare the box, warranty card, and serial numbers for matching fonts, dates, and reference codes.
Why the moon phase disc exposes most fakes
The moon phase is the hardest part of this watch to copy at low cost. A genuine disc is a thin metal plate with a textured sky and applied or stamped detail that catches light in sections. Replica makers print the entire scene in one pass, which produces a flat blue field with soft stars and a moon that reflects light the same way across its whole surface. Move the watch under a lamp. If the sky, stars, and moon all brighten together, treat the disc as suspect.
Movement and case back checks
Compare the engraving on the case back to a catalog image at 10x. Fake engravings sit shallow, with rounded letter edges and uneven spacing between words. Real engraving has crisp walls and consistent depth across the whole text block. On display-back examples, look at the bridges for Geneva stripes with clean edges, polished bevels, and circular graining on the wheels. A common fake movement shows machine-applied stripes that stop short of the bevel and screws with damaged slots.
Papers, serials, and price signals
Ask for the original invoice, warranty card, and service records, then confirm the serial on the card matches the case back and the movement. A price far below market for a moon phase Jules Audemars is the single most reliable warning sign. Sellers of counterfeit goods also avoid in-person inspection, refuse to open the case back at a watchmaker, and push for payment methods with no buyer protection.
When to stop and walk away
End the inspection if the seller blocks a watchmaker's verification, if the serials do not match across the card and case, or if the moon disc shows flat print. Selling or buying a counterfeit watch is illegal in the United States and most other markets, so document what you find, keep your payment records, and report the listing to the platform and to the relevant authority.