The short answer
No Omega reference number pairs 151 with Master Chronometer. The 151.xx prefix comes from the Constellation Double Eagle family Omega sold in the mid 2000s. Master Chronometer is a newer label: Omega brought it in during 2015, and the modern Constellation picked it up under reference prefixes starting 130 and 131. When a listing reads replica Constellation Master Chronometer 151, you are reading seller shorthand, not an Omega catalogue entry. That matters, because the two names promise different things about the case and the movement.
How the two labels got glued together
Replica sellers stack keywords. They pull the old 151 prefix because it shows up in search results for older Constellation models, then bolt on Master Chronometer because that phrase signals modern spec and a higher price. The collage is not a lie about one specific watch, but it does not describe one either. If you want the modern anti-magnetic Constellation, shop the 131 references. If you want the older Double Eagle look, shop the 151 references. Be clear with yourself about which one you are chasing before you open a single photo.
What a solid replica gets right
- Case and size. Modern Constellation Master Chronometer cases run 38mm and 41mm. Older 151 Double Eagles sat closer to 35mm to 38mm with a thicker profile. Know which footprint you want.
- The claws. The two griffes at 3 and 9 o'clock are the signature. On a good replica they are polished, sit flush against the bezel, and taper cleanly where they meet the case. On a cheap one they look stamped and sit proud.
- The bezel. Steel Master Chronometer Constellations use a tungsten carbide ring with a mirror finish. Replicas tend to use polished steel, which scratches fast and reads slightly warmer in tone.
- The dial. Applied star at 6 o'clock, crisp printing, and a date aperture with clean edges. The pie-pan slope on Globemaster-style dials is often too shallow on fakes.
- Sapphire on both sides. The caseback should show the 8-lobed Constellation medallion and the movement behind it.
Where replicas fall down
- Bracelet end links that do not sit flush with the case, and a clasp that feels thin in the hand.
- Hands and markers that lack depth, with flat white paint instead of applied metal.
- Crown threads that feel gritty or strip after a few months of regular winding.
- Rotor engraving that is shallow and set in the wrong font.
The movement question
Master Chronometer is not a phrase Omega invented on its own. Each watch is certified by METAS, the Swiss federal institute of metrology, across eight tests. Those cover exposure to a 15,000 gauss magnetic field, a daily rate window of 0 to +5 seconds, and checks performed with the watch fully assembled rather than as a bare movement. A genuine Constellation Master Chronometer runs a Calibre 8900 or 8901: twin barrel, 60 hours of reserve, 3.5 Hz.
No replica carries that. Most run a decorated ETA 2824, a Sellita SW200, or a Seagull ST21. A smaller number use Chinese copies of the 8500 family with a co-axial style escapement. When a seller claims the watch is METAS certified, ask for the card and the movement number. Genuine watches match. Replicas have no card to show.
Checklist before you pay
- Ask for photos of the claws from a low angle, not only straight on.
- Ask for a video of the seconds hand. 3.5 Hz looks different from 4 Hz.
- Ask what movement is inside, by name and by factory.
- Check the caseback for the 8-lobed medallion and honest engraving depth.
- Confirm the case size in millimeters, not a vague "40mm class".
- Get the return window in writing.
What to pay
A replica of this tier sits between roughly $250 and $500 depending on movement and bracelet. Below $150 you are buying a costume piece with a printed dial and a plated case. Above $600 you are in territory where a used quartz Constellation starts to make more sense.
Bottom line
The name on the listing is a mashup of two Omega eras. Judge the watch on the case, the claws, the dial finishing, and the movement, and ignore the certification language. If a seller leans hard on the words Master Chronometer without naming the calibre, that alone tells you plenty.