The Topper Blog consists mainly of original writing by Rob & Russ Caplan with occasional special contributions and interviews. All photography in the blog is taken at Topper Fine Jewelers , or on location unless otherwise indicated in the photo captions.

The 2016 OMEGA Planet Ocean 600M GMT

The 2016 OMEGA Seamaster Planet Ocean 600M Master Chronometer GMT

A little over a month ago, we wrote a blog post about the 43.5mm Planet Ocean and the 39.5mm Planet Ocean. Now, it's time to look at the new black and white bezel GMT announced this year at Baselworld 2016, specifically the bracelet version of this model.

The first thing to note about the watch is that the diameter is unchanged from previous versions of the Planet Ocean GMT. While the three hand Planet Ocean models shrunk down from the previous generation's case sizes of 42mm and 45.5mm, the GMT model remains at 43.5mm. With the prior generation of Planet Ocean, we observed many people purchasing the GMT model because they found it to be the ideal size for their wrist. Now that the standard three hand models comes in a 43.5mm, it seems more likely that the 2016 Planet Ocean GMT will be purchased more specifically for the GMT complication, or is enamored by the look. It is slightly thinner (17.25mm vs. 17.04mm) than the previous Planet Ocean GMT, and is exactly 1mm thicker than the 2016 three hand Planet Ocean models (16.04mm).

The watch's most dominant feature is the new black and white bezel. Day/Night GMT bezels have been a signature aesthetic feature of some of the most successful GMT watches ever, including the Rolex GMT Master II and Omega's own 50th Anniversary Seamaster in the late 1990s. However, this one brings something new in the way that the black and white mirror each other, and how it is constructed. Unlike its anodized aluminum ancestor, or Rolex's GMT II which is made in one color ceramic with the second half subsequently treated to change color, the new Planet Ocean GMT features two naturally distinct ceramic colors. Aside from the Day/Night effect of the bezel, the primary purpose of the watch being for travel rather than diving also necessitates a different treatment on the bezel markings. The minute indices of the GMT are segmented throughout the entire interior of the bezel. While all other Planet Ocean models feature a separate treatment for the first fifteen minutes, including a solid arc on the bezel interior in place of the minute track and individual radius indices for each minute.

The 24-hour bezel works in concert with the GMT movement and its convenient 'quick hour' function. In the first setting position of the screw-down crown, the movement provides for an easy hour-to-hour adjustment to local time without stopping the watch or disrupting the (home time) GMT hand.

The bicolored day/night ceramic bezel and shiny black ceramic dial of the Planet Ocean GMT.

Most of the other details of the watch are the same as the other new 43.5mm pieces. The dials are the same glossy style as on the titanium Liquidmetal® models of the previous generation. While the last generation of Planet Ocean GMT models featured a matte black dials, the new pieces sport glossy ceramic (ZrO2) dials like those of the Dark Side of the Moon models.

The bracelet has all of the updates of the standard 43.5mm Planet Ocean. Like that watch, the center links that abut the case are shorter than the prior generation allowing a sharper transition away from the case. This in theory should allow a better fit for smaller wrist sizes. The clasp has also been upgraded to feature the same extendable foldover rack-and-pusher mechanism resident on the Seamaster 300 and the Speedmaster Mark II. This upgrade allows adjustment to five different positions adding up to 9.60 mm in length. The "alveol" screw-in caseback seems a little thinner than the previous caseback and its design ensures that the caseback text is always properly aligned to the watch.

When discussing the 43.5mm non GMT Planet Ocean, we examined in great detail how the movements in the Planet Ocean had progressed over the years as the watch transitioned from the 2500c to 2500d to 8500b and now to the new 8900 Calibre. (For those interested it is posted at the bottom of this article.)

This watch features the 8906 caliber which replaces the 8605 of the previous generation. The 8605 was a parallel movement to the 8500b. Accordingly, it featured the dual-barrel power reserve which both elongated the power reserve up to 60 hours and allowed the watch to maintain consistent accuracy throughout all levels of charge. A time zone function that allowed changing the hour hand (as when travelling across time zones) without hacking the watch, and Nivachoc shock absorber that was an improvement over the 2500's Incabloc shock absorber. In addition, it had a more shock resistant and magnetism resistant silicon hairspring.

The 8906 takes all of these mechanical innovations and upgrades them by making all regulatory components, such as the escapement wheel and pallet fork, out of anti magnetic materials. Furthermore, though the 8906 is still certified by the COSC before it is cased in the watch, it undergoes further testing as a fully cased watch by the third party testing organization, Swiss Federal Institute of Metrology (METAS). METAS testing is done to externally validate quality standards beyond those used by the COSC. Watches that pass the METAS certification process earn the designation of Master Chronometer. Where the COSC rates a fully charged watch movement in five positions, Master Chronometer watches complete a second certification that essentially validate the capabilities of the 8500C. METAS ensures that the watches are accurate not just to the COSC standard of -4 to +6 seconds a day, but that they are accurate to their stricter specification of zero to +5 seconds a day.

METAS also subjects the watch to a series of tests that OMEGA innovations only first seen in the 8500A enable it to pass. For instance, one of the tests ensures that the rate is fairly close when the watch is at both a 33% charge and at full charge. Another test insures that the power reserve achieves the promised 60 hours. This is only possible due to the use of dual barrels on all 8500 Calibres. There are also tests such as the 15,000 gauss magnetic resistance test that only the most recent version C of the 8500 could pass. METAS also performs other tests such as water resistance, which is only possible to validate on a fully cased watch.

This watch retails for $8,000, around the same price as the previous version Planet Ocean GMT $7,800. How do you like the new Planet Ocean GMT?

The “night” side of the new bicolored ceramic bezel.

The hand set of the new Planet Ocean GMT. Note the monochromatic color treatment (no orange) on the 2016 GMT hand.

The “day” side of the new bicolored ceramic bezel.

The fold-over clasp of the steel Planet Ocean bracelet (protective plastics still in place).

The new Planet Ocean GMT (left) is slightly thinner that the previous generation (right) due partially to the new alveol screw-in case back.

Notable visual changes on the new Planet Ocean GMT (left) from the prior generation (right) include the bi-ceramic bezel, shiny ceramic dial, monochromatic GMT hand, and shorter, more articulating bracelet case link.

Side by side comparison of the new Planet Ocean GMT (left) with the prior generation (right).

Impressive lume signature of the new Planet Ocean GMT. Note the use of contrasting green Superluminova on the minute hand and bezel pip.

The sapphire window of the new alveol screw-in caseback gives a view into the balance wheel and heat-treated black screws of the Master Co-Axial certified Calibre 8906.

Another view into the movement showing the dual barrels that provide the Planet Ocean GMT with its 60-hour power reserve.

A Burlingame Avenue wrist shot of the new Planet Ocean GMT. Note how the new shorter case links provide a more form fitting feel on a 7-inch wrist.

Following is an excerpt from a previous Topper article describing the evolution of the OMEGA movements in three-hand Planet Ocean models.

2500 Series 2004-2011

When the Planet Ocean first came out in 2004, it was OMEGA's most robust dive watch in production at the time. At 600M, it featured double the water resistance of the extremely popular Seamaster Diver 300 M. It also featured a version of the Calibre 2500.

Examples of our best selling Calibre 2500 Planet Oceans were the 42mm 2201.50.00 and the 45mm 2208.50.00. At that point, OMEGA was on its second upgrade of the movement which was termed the Calibre 2500C. As we described earlier in the year when looking at the new Globemaster models, the 2500 Calibre made it's debut in 1999 and has since gone through three iterations of the original Calibre 2500A, namely the B, C, and D.

The B was upgraded from the A by way of a sturdier palette bridge.The change in the C version was a slowing of the movement from 28,800 vph (4Hz) to 25,200 vph (3.5Hz). Shortly before the 2500 Calibre Planet Ocean was discontinued in 2011, OMEGA shipped a small number of watches featuring the 2500D caliber.

The D calibre, as in the current Seamaster Diver 300 M, is distinct from previous versions in that it features a full three-level escapement. The three-level escapement makes the movement more stable, and is how the inventor of co-axial mechanism, George Daniels, originally envisioned it.

As a side note, if you are thinking about buying a 2500 Caliber Planet Ocean and want to know if it's a C or D caliber, you can tell by having a dealer look up the serial number on the OMEGA Extranet or by looking at the date wheel. Assuming everything is original, and the ten digit on the date wheel looks like a capital "I", then it's a C Calibre. If that digit has a serif on top like this "1", then it's a D calibre.

8500 Calibre 2011 to Current

When the Planet Ocean was redesigned in 2011, it switched to the 8500B Calibre. The same 42mm and 45mm sizes were maintained, and all three-hand watches came in both sizes. The aforementioned 2201.50.00 evolved into the 232.30.42.21.01.001 and the 45mm 2208.50.00 evolved into 232.30.46.21.01.002. The watches were immediately distinguishable from the 2500 series as they featured display case backs, and thicker cases. Specifically, the 42mm 2500 Calibre Planet Ocean featured a 14.2mm case while the 8500 Calibre features a 15.7mm case.

As for the movement, the 8500 Calibre was a significant improvement over the 2500. When the 8500 made its debut in 2007, it featured several advanced features not found on the 2500. Among the most significant was the dual-barrel power reserve which both elongated the power reserve up to 60 hours and allowed the watch to maintain consistent accuracy throughout all levels of charge. The 8500 also included a time zone function that allowed changing the hour hand (as when travelling across time zones) without hacking the watch, and Nivachoc shock absorber that was an improvement over the 2500's Incabloc shock absorber. By 2011, when the Planet Ocean received the 8500 Calibre, the movement was on its second iteration (8500B) and featured a more shock resistant and magnetism resistant silicon hairspring.

Aside from the movement change, there were a number of significant changes introduced in the 8500 Calibre Planet Oceans. Ceramic bezels were introduced on all black, gray, white and blue bezels. The one notable exception was orange. While OMEGA did feature an 8500 calibre platinum limited edition with an orange bezel, all of the steel 8500 models sported the same anodized aluminum bezels as the prior generation 2500 Calibres.

8500 Calibre references paired blue dials (with the exception of the GoodPlanet GMT) with a grade 5 titanium case. Almost all blue dials also featured Liquidmetal® scales for the numbers and indices. On these watches, their ceramic bezels had been made with a shallow trough where liquid metal was poured then cooled. The effect was a great looking shimmer and a durable finish. In fact, I've never seen a customer bring in a watch with a visible scratch on Liquidmetal®.

While Liquidmetal® was on the titanium models (and for that matter the Blancpain Fifty Fathoms Bathyscaphe and OMEGA 300 Master Co-Axial), most of the ceramic models in the 8500 Planet Ocean do not feature Liquidmetal®. Instead, they feature ceramic bezels with a plating of chromium nitride. Though also attractive, chromium nitride seemed to attract similar scratches to the anodized aluminum bezels of the 2500 Calibre.

8900 Calibre 2016

The new Planet Ocean models feature the same 8900 Calibre movement announced in the Globemaster at Baselworld 2015, and have also earned the designation of 'Master Chronometer'.

In essence, this movement is an upgraded version of the 8500B in which components such as the escapement wheel and pallet fork are also made of anti magnetic materials. Furthermore, though the 8900 is still certified by the COSC before it is cased in the watch, it undergoes further testing as a fully cased watch by the third party testing organization, Swiss Federal Institute of Metrology (METAS). METAS testing is done to externally validate quality standards beyond those used by the COSC. Watches that pass the METAS certification process earn the designation of Master Chronometer.

Where the COSC rates a fully charged watch movement in five positions, Master Chronometer watches complete a second certification that essentially validate the capabilities of the 8500C. METAS ensures that the watches are accurate not just to the COSC standard of -4 to +6 seconds a day, but that they are accurate to their stricter specification of zero to +5 seconds a day.

METAS also subject the watch to a series of tests that OMEGA innovations only first seen in the 8500A enable it to pass. For instance, one of the tests ensures that the rate is fairly close when the watch is at both a 33% charge and at full charge. Another test insures that the power reserve achieves the promised 60 hours. This is only possible due to the use of dual barrels on all 8500 Calibres. There are also tests such as the 15,000 gauss magnetic resistance test that only the most recent version C of the 8500 could pass. METAS also performs other tests such as water resistance, which is only possible to validate on a fully cased watches. WatchTime magazine has a great article that describes the METAS test in more detail. OMEGA also provides a description of the METAS certification here.

The Topper Blog consists mainly of original writing by Rob & Russ Caplan with occasional special contributions and interviews. All photography in the blog is taken at Topper Fine Jewelers , or on location unless otherwise indicated in the photo captions.