The Omega Constellation 38mm has a 38.0 mm case and a thickness of about 12.3 mm. A replica listed at 40 mm or 11 mm is not a 1:1 copy of this reference. Get caliper photos before you pay.
Start with three numbers
Ask the seller for three measurements: diameter, thickness, and weight on a scale.
- Diameter: 38.0 mm across the case, not the bezel.
- Thickness: about 12.3 mm from caseback to crystal.
- Weight: a steel 38mm on the full bracelet sits in the 130 g to 150 g range. Hollow-link copies read under 110 g.
If the seller cannot state the calibre or the thickness, treat the listing as unknown. Ask for a photo of the watch on a kitchen scale with the bracelet at full length.
Fake Constellation 38mm vs Replica: Which to Pick
Dial and claws
The dial carries two half-moon facets at 3 and 9 o'clock. On the original the facet edge meets the case at a sharp line. On most replicas the facet is stamped and the edge is rounded.
Fake Constellation 38mm for Sale: What to Check Before You Pay
The star at 6 o'clock is applied on the 38mm, not printed. Run a fingernail across it. A printed star sits flat against the dial.
The date window sits at 6 o'clock. Check the cut. The aperture edge is beveled and the date disc has a matte finish. Replicas show a glossy disc and a square, sharp cut.
Bezel
The Roman numerals on the bezel are engraved and filled. Look at the X and the V. Copies cut the numerals shallow, and the fill sits above the surface instead of inside the groove.
Movement
Reference 131.10.38 uses calibre 8800. The spec sheet reads: Co-Axial escapement, Master Chronometer certification, 25,200 vph, 55 hour power reserve, silicon hairspring, free-sprung balance with no regulator index.
Look at the balance through the caseback. A regulator arm with two pins means the movement is a decorated clone, not an 8800. Replicas often use a Miyota base with a printed rotor.
Bracelet and clasp
The mono-rang bracelet tapers toward the clasp. Check the link gaps at the case. Wide, uneven gaps point to a cast bracelet. Check the clasp engraving depth and the fold-over safety tab.
Price and paperwork
A new steel 38mm Constellation lists above $6,000 USD. Replica prices run $300 to $800. A seller asking $2,000 for a replica is not selling at replica price. Ask for the reference number and compare it against photos of the real reference.
No photo set answers everything. Ask for a short video with the seconds hand running and the crown pulled to the time-setting position.