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In-house manufacture caliber · caliber Omega Cal. 8501: Co-Axial Master Chronometer automatic, 25,200bph, 60h PR, 30j; METAS-certified, anti-magnetic; used in Constellation Modern 41 · 60h power reserve (2.5 days)
Medium-large: suits wrists 6.5 in+ (16.5 cm+)
41 mm case. Wears confidently on average to larger wrists. May overhang on slender builds.

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Authentication

The deeply engraved Constellation star on the caseback is the single most reliable authentication marker; a flat stamped star indicates a non-genuine or replacement caseback.

Known issues in the market
  • Counterfeit Constellation casebacks have a flat stamped star rather than a deeply engraved one; the relief should be felt with a fingernail.
  • The integrated claw lug tips are thin and crack under prying; inspect for any cracking at the claw tips under a loupe.
  • The integrated bracelet on Constellation models is Omega-specific; any non-Omega integrated bracelet is an incorrect replacement.
AreaWhat to checkWhat is correctRed flag
casebackStar medallion reliefStar deeply engraved with relief felt under fingernail pressure, sharp star-point edgesFlat stamped star with no tactile relief; star with rounded points indicating wear or a cast fake
caseClaw lug tipsClaw tips intact with no cracking, sharp edge at the tip consistent with factory finishCracked or chipped claw tips; any claw tip that shows a stress fracture under loupe examination
braceletIntegrated bracelet identityOmega-specific integrated bracelet with signed deployant clasp, correct link taper toward the claspNon-Omega integrated bracelet; any bracelet without Omega signed clasp
Common legitimate replacements
  • Integrated bracelets are a known replacement target on Constellation models; confirm the clasp is Omega-signed.
  • Claw lug damage is common on previously owned examples; any repair welding at the claw tips affects value.
Expert resources: Omega.com Constellation Modern documentation. Omega Forums for integrated bracelet and caseback authentication comparison.

Authentication guide

Last reviewed June 2026

The modern Constellation is defined by its four "claw" elements holding the sapphire crystal to the case, and the applied star at 6 o'clock. Cal. 8501 is Co-Axial Master Chronometer. The claws are a casting element -- they are part of the case, not applied accessories, and their geometry is precise.

Known reproduction risks

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MEDIUM

Reproduction with applied claws rather than integral case casting

  • Visible join line at the base of a claw -- indicates applied rather than cast construction
  • Claws asymmetric when viewed from above
  • Claw finish inconsistent between positions

The Constellation is faked in lower volume than the Seamaster or Aqua Terra. The cast claw architecture is difficult to replicate correctly.

Dial variants by era

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EraDescriptionIdentifiers
2015 to present (cal. 8501)Round 41mm case with four polished claws at the compass points holding the sapphire crystal. Applied star at 6 o'clock. Integrated bracelet with no visible attachment lugs. Black and silver dial colorways. Date window at 3 o'clock. "Constellation" text on dial.
  • Four polished claws at 12, 3, 6, and 9 positions -- the Constellation's defining case element
  • Applied star at 6 o'clock on the dial
  • Integrated bracelet design with no visible lug attachment
  • "Constellation" and "Master Chronometer" text on dial
  • Date window at 3 o'clock
  • No visible crown -- recessed crown between the case and bracelet

Service part flags

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Case claws

Original: The four claws are cast as part of the case body -- they are not applied separately. Each claw has a polished finish on specific surfaces and brushed on others. The geometry is precise and the claws are symmetric. Any claw that appears applied, misaligned, or differently finished than the others has been modified or repaired.

Replacement tells
  • One or more claws with a different finish than the others -- indicates a repair or replacement
  • Claws asymmetric or misaligned when viewed from above
  • Visible join line at the base of a claw where it meets the case -- suggests post-assembly attachment
Star at 6 o'clock

Original: Applied metal star at 6 o'clock on the dial. The star has specific proportions and is polished to the Omega standard. The star is a Constellation heritage element and should match the finish of the other applied indices.

Replacement tells
  • Star absent from a watch sold as a Constellation
  • Star present but with different proportions or finish than the dial indices
  • Star appears glued rather than correctly applied with prongs
Integrated bracelet

Original: The bracelet flows directly from the case with no visible attachment point. Bracelet polishing follows specific surface designations. The deployant clasp carries the Omega logo.

Replacement tells
  • Visible gap at the case-bracelet junction
  • Deployant clasp without Omega logo
  • Bracelet links polished on surfaces that should be brushed

Case back markings

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2015 to present
  • Caliber 8501 designation
  • Constellation observatory motif
  • "CO-AXIAL MASTER CHRONOMETER" text
  • "100 M / 330 FT" water resistance
  • Case reference and serial number
  • "OMEGA" and "SWISS MADE"

Movement tells

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  • Cal. 8501 is Co-Axial Master Chronometer with bidirectional automatic winding. Power reserve is 60 hours.
  • The co-axial escapement geometry applies. The movement is not visible without opening the case. A watchmaker report confirming caliber identity is the recommended step.
  • The integrated bracelet makes certain service operations more complex -- specifically, a watchmaker accessing the crown or caseback requires knowledge of the Constellation case architecture.
Sources: Omega Constellation official; Hodinkee Constellation Master Chronometer review.

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