The Seiko Astron GPS Solar, launched in 2012, is the first wristwatch that sets itself by GPS satellite signals and is powered by light. It has a titanium case with a hard coating, a solar cell under the dial and a GPS receiver that finds the local time zone and sets the time anywhere in the world. Seiko’s design pages present it as a world first; I did not find reliable figures for the case size, battery reserve or water resistance of the first model, so they are not given here.

The Astron name goes back to Seiko’s 1969 Quartz Astron, the first quartz wristwatch, and the 2012 model was presented as a return to that spirit of technical firsts. Later versions made the case slimmer and added more features.

The first Astron GPS Solar was received as an impressive but chunky technical showpiece, popular with frequent travellers. The Astron line remains in production in newer generations, while the first 2012 model has been replaced.