Four New Astron GPS Solar Dual-Time Chronographs Bolster Seiko’s Precision Navigation

Seiko redefined horology in 2012 with its pioneering Astron GPS Solar timepiece. Its seamless link to the Global Positioning System (GPS) was the standout feature; it adjusted to any time zone with a single touch. What made the creation even more impressive was its self-sustaining power source, which derived energy from light or the sun. 

Of course, the Astron collection has evolved over the years. Four new GPS Solar Dual-Time Chronograph models, just launched by Seiko as part of the Astron series, showcase the watchmaker’s stupendous progress in harnessing solar power for timepieces. Featuring GPS-controlled time synchronisation and solar-powered efficiency, the four new models include Ref. SSH175 (blue-grey), Ref. SSH177 (grey), Ref. SSH179 (black), and Ref. SSH180, a 1,500-piece limited-edition deep navy blue variant.

A GMT watch as well as a dual-time watch show two time zones, but they work differently. A GMT watch often has an extra 24-hour hand that rotates once a day, pointing to a 24-hour scale on the bezel or the dial; this allows the wearer to track a second time zone while reserving the primary hands for local time. This is useful for tourists who often change time zones. A dual-time watch, on the other hand, features two distinct hour indications, typically in the form of a subdial or an independent second hour hand that may be set independently of the main time display. This configuration is very convenient for individuals who need to monitor two fixed time zones simultaneously. 

Each of the new Seiko chronographs comes on a 44 mm titanium angular shaped case; it has a 60-minute bezel and a fluted crown positioned at 3 o’clock, flanked by two robust block-shaped pushers at 2 o’clock and 4 o’clock. The limited-edition model gets a faceted dodecagonal rose gold-coloured titanium bezel and rose gold-coloured accents on the hour markers. The dial layout remains true to the Astron’s signature style, packed with functional elements.

Each reference also features three subdials, including a dual-time register at 6 o’clock, a multifunctional mode selector at 9 o’clock that also integrates a power reserve indicator with a day of the week display, and a 1/20th of a second chronograph counter at 12 o’clock. Applied hour markers and hour, minute, and second hands are filled with Lumibrite; a 24-hour indicator rests at 4 o’clock while a date window at 4:30 adds to its practicality.

The markers on the subdials at 12 o’clock and 6 o’clock are diamond-cut, and the main radiant dial features a wide three-dimensional pattern consisting of horizontal stripes. Also, the inner bezel houses engraved city codes that are placed in accordance with UTC/GMT, just above the minute markings. Other functions of the collection include a perpetual calendar up to February 28, 2100, DST (Daylight Saving Time), world time function (38 cities), and satellite acquisition status display function. 

Running the watches is GPS Solar OCalibre 5X83 with a power reserve of six months (when fully charged); each watch can save power for two years. When the dial detects sunlight, the watch connects to the GPS satellite network and adjusts automatically to the correct time. If the watch is hidden from light, it remembers the time of its last successful manual connection and attempts to receive the GPS signal again at that same time. The solid screw-down titanium caseback on each watch displays an intricately engraved three-dimensional globe. A multi-row bracelet with mirror polishing and hairline finishing completes the look.