Seamaster Planet Ocean 600M Co-Axial 43.5 Master Chronometer Sedna Gold / Blue / Strap

In Context

At 43.5 mm it is a large watch — well above this catalogue’s 40 mm median, and enough to dominate a narrow wrist. At 16.04 mm it is very tall, and sits high off the wrist. The case back is open, so the movement is visible without taking the watch apart, and the sapphire crystal will resist everything short of deliberate abuse. 600 m is a professional diving rating, far past any demand a wrist is likely to make of it.

The movement winds itself from the motion of your wrist. 60 hours of reserve is enough to set it down on Friday evening and find it still running on Monday. At 25,200 vph the seconds hand advances 7 times a second.

215.63.44.21.03.001 stands on its own in this catalogue — no other reference here shares its base number. It pairs a blue dial with a sedna gold case. Introduced in 2016.

The 8901 is the 8900 with an 18-carat Sedna gold rotor and balance bridge. It is the version of Omega's two-barrel Master Chronometer movement fitted to gold-cased watches. It powers 16 watches in this library. The [8900](/calibers/omega-8900) is the co-axial caliber Omega introduced in the Globemaster in 2015 as the first Master Chronometer, certified by METAS to 15,000 gauss, with two barrels in series for 60 hours, a silicon balance spring on a free-sprung balance, 39 jewels and a beat of 25,200 vph at 29 mm across. The 8901 is mechanically the same movement with its rotor and balance bridge made in Sedna gold, and the gold Globemaster of 2015 was among the first watches to carry the certificate. The [Master Chronometer piece](/blog/master-chronometer-what-metas-tests) sets out what it measures. In the library it powers 6 [Aqua Terras](/brands/omega/aqua-terra), 4 [De Villes](/brands/omega/de-ville), 3 [Constellations](/brands/omega/constellation), 2 [Globemasters](/brands/omega/globemaster) and one [Planet Ocean](/brands/omega/seamaster-planet-ocean), 13 of them at 41 mm. The [8801](/calibers/omega-8801) is the gold-rotor version of the single-barrel 8800.

15 other watches in the library run the Omega 8901.

Omega

Seamaster Aqua Terra 150M Master Chronometer 41 Moonshine Gold / Green / Rubber

220.52.41.21.10.001 · 41 mm

Omega

Seamaster Aqua Terra 150M Master Chronometer 41 Sedna Gold / Silver / Bracelet

220.50.41.21.02.001 · 41 mm

Omega

Constellation Master Chronometer 41 Stainless Steel / Sedna Gold / Ceramic / Blue

131.23.41.21.03.001 · 41 mm

Omega

Seamaster Aqua Terra 150M Master Chronometer 41 Sedna Gold / Brown / Alligator

220.53.41.21.13.001 · 41 mm