Seiko Astron GPS Solar 2025 Editions Reign in Purple Splendor

Since its high-profile revival in 2012, the Seiko Astron has continuously evolved in both its technical capabilities and in its size and overall aesthetics. As I explore in greater detail in this little treatise on the Astron models and their esteemed history, the founding member of this modern, solar-powered, GPS-equipped Astron family debuted in an imposing 47mm case in steel, with one dial option, in matte black. Since then, Seiko has refined the elements that necessitated the large dimensions and limited colorways — i.e., reducing the size of the quartz movement’s GPS-reception antenna and improving the efficiency of the dial’s solar cell — and the result has been a plethora of intriguing interpretations. The latest and perhaps most distinguished in terms of colorway dropped just recently.  The Astron GPS Solar SSJ029 and Astron GPS Solar Chronograph SSH171, both limited editions of 1,500 pieces, feature glittering, violet-hued dials that Seiko says are inspired by “cherry blossoms blooming under the stars.”

Both of the new watches have cases and bracelets made from titanium and treated with an extra-hard, scratch-resistant black coating that emphasizes the night-sky motif that these models are shooting for aesthetically. The cases are 42mm in diameter, 12.4mm thick, and 47.9mm lug to lug — the result of the aforementioned streamlining since the oversized original’s debut. The dials’ gradient purple colors are enhanced by a sprinkle of starry glitter and a pattern on the outer circumference resembling star trails. The hands and hour markers are finished with a layer of LumiBrite, Seiko’s proprietary luminous substance, enabling them to glow brightly in the dark. The simpler three-hand model (SSJ029) has a date window at 3 o’clock and an analog indicator for the battery’s power reserve between 7 and 8 o’clock; the chronograph-equipped SSH171 places its date window at 4:30 and features subdials at 12, 9, and 6 o’clock to host an array of added functions, including chronograph readouts (to 1/20th-second), power reserve, a day-of-the-week display, and a dual-time indication. 

The movements inside both of these Astron limited editions — Caliber 3X62 in the time-date model and Caliber 5X52 in the chronograph — both come from Seiko’s innovative series of quartz movements powered by light and incorporating GPS signal reception for automatic time and time-zone adjustment. Their ultra-efficient batteries operate for up to 6 months on a full charge from sunlight or any light source, with a “power save” mode up to two years when the watch is left idle. The GPS satellite signals picked up by the movement’s miniaturized antenna ensure the watch’s timekeeping is reliably accurate and precise — losing or gaining only 15 seconds per month in the absence of a signal. The cases that houses these cutting-edge engines are magnetic-resistant to 4,800 A/m and water-resistant to 100 meters. The black-coated, hypoallergenic, titanium bracelets fasten to the wrist with a three-fold push-button clasp and an adjustment system to fine-tune the bracelet length.

The Seiko Astron GPS Solar Limited Editions for 2025 feature specially engraved screw-down casebacks with “Limited Edition” and the watch’s serial number. Prices are $2,600 (Ref. SSJ029) and $2,700 (SSH171).