While the brand is arguably best known for its traditional mechanical watches, Seiko also produces a variety of thoroughly modern timepieces in the form of the Astron series, which is characterized by its use of solar-powered movements with radio-controlled GPS timekeeping. Within the United States, these models rarely receive the same attention that is enjoyed by the brand’s mechanical pieces, although Seiko has been continuously developing the Aston platform over the years, and the brand has just announced a new dual-time chronograph version for one of its latest new releases of 2024. The new Seiko Astron GPS Solar Dual-Time Chronograph series spans four different references, which include the SSH151, SSH153, SSH155, and SSH156, and while the first three models will be joining the collection as standard-production offerings, the final version will be produced as a limited edition of 1,000 examples to celebrate the 100th anniversary of the Seiko brand and the legacy of the company’s founder, Kintaro Hattori.

The four new Seiko Astron GPS Solar Dual-Time Chronograph watches are all variations of the same core model; however, because the limited-edition SSH156 is fitted with a different style of bezel, its dimensions are slightly different than those of its standard-production siblings. Consequently, the SSH151, SSH153, and SSH155 models all have cases that measure 43.3mm in diameter by 13.4mm thick, while the limited-edition SSH156 is slightly larger at 43.4mm in diameter by 14.1mm thick. That said, all four of the new Seiko Astron GPS Solar Dual-Time Chronograph watches are crafted from titanium and they feature Seiko’s “super-hard” coating in either clear or black. 

All four of the new Seiko Astron GPS Solar Dual-Time Chronograph watches follow the same core design with double-domed sapphire crystals above their dials, titanium bezels with ceramic inserts, crowns flanked by a set of pushers on the 3 o’clock side of the case, and solid screw-down casebacks that help ensure the 100 meters of water resistance that is offered across the collection. With that in mind, while the trio of standard-production models all feature Arabic numeral minute markings and the word “Chronograph” engraved into their bezels, the limited-edition version gets fitted with a faceted black ceramic bezel for a more ornate appearance, and it also receives gold-finished accents with a black ceramic cap set into the tip of its crown.

While all four of the new Seiko Astron GPS Solar Dual-Time Chronograph watches are fitted with the collection’s signature semi-integrated bracelet, the finishing and materials differ slightly across the various models. The SSH151 and SSH153 both have titanium bracelets that offer a natural metal appearance, while the SSH155 has a black-finished bracelet to match its case, and the limited-edition 100th anniversary SSH156 gets fitted with a black-finished titanium bracelet that has black ceramic center links with glossy high-polished middle sections. Additionally, unlike the three standard-production models from the lineup, the limited edition SSH156 also comes packaged with an alternate black silicone strap that is completed by a signed folding clasp.

The dials fitted to the new Seiko Astron GPS Solar Dual-Time Chronograph watches all offer the same overall design and layout, although the colors and finishing on them differ between the different models. While it offers a similar overall design as the brand’s existing Astron chronograph watches, the sub-dials have been rearranged into a 6-9-12 formation, and they now serve different purposes. At the top of the dial is a 1/20th second totalizer for the chronograph, while the register sitting opposite it at 6 o’clock is a dual-timezone display that turns into a 12-hour counter when the chronograph is activated. Meanwhile, the register at 9 o’clock is also the multi-function variety, and it serves as a day display in addition to being an indicator for both the power reserve and the mode selection of the watch.

Among the three standard-production Seiko Astron GPS Solar Dual-Time Chronograph watches, the SSH151 is the version fitted with a black dial that has silver registers, while the SSH153 is the inverted model that has a silver dial with black registers, and the SSH155 receives an all-black dial to complement the black finish on its case and bracelet. Meanwhile, the limited-edition 100th anniversary SSH156 is fitted with a black dial that has yellow gold accents, and while it also features a subtle radial pattern on its dial (versus the vertical line motif of the standard-catalog models), all four of the new Astron GPS Solar Dual-Time Chronograph watches have Seiko’s Lumibrite luminescent material applied to their hands and hour markers to aid with low-light visibility.

Making its debut in the new Seiko Astron GPS Solar Dual-Time Chronograph watches is the brand’s Caliber 5X83 radio-controlled solar quartz movement, which automatically synchronizes itself to a GPS signal to ensure accurate timekeeping. With that in mind, the movement can also be manually synchronized by simply pressing one of the buttons that are located on the side of the watch’s case. In addition to being solar-powered and offering both dual-time and chronograph functionality, the Seiko Cal. 5X83 also includes a perpetual calendar with automatic daylight savings time adjustment, and it even offers a world time feature that allows users to easily swap the timezone that is displayed by the primary dial.

While the quartet of new Seiko Astron GPS Solar Dual-Time Chronograph watches feel very familiar from an aesthetic standpoint, their advanced features ultimately make them highly practical timepieces that push the boundaries of what is possible with an analog wristwatch. In regards to pricing, the SSH151 and SSH153 both cost $2,500 USD, while the all-black SSH155 is priced at $2,700 USD, and the 1,000-piece limited edition SSH156 is naturally the most expensive at $3,900 USD. The four models are scheduled to be available for purchase in June/July 2024, and while this is quite a bit more expensive than what it takes to acquire one of the brand’s fan-favorite Prospex divers, it’s undeniable that the Seiko Astron GPS Solar models offer a level of functionality that simply isn’t possible with a traditional mechanical movement. For more information on the Seiko Astron GPS Solar Dual-Time Chronograph collection, please visit the brand’s website.