The Astron wristwatch, formally known as the Seiko Quartz-Astron 35SQ, was the world's first "quartz clock" wristwatch. It is now registered on the List of IEEE Milestones as a key advance in electrical engineering.
The Astron was unveiled in Tokyo on December 25, 1969, after ten years of research and development at Suwa Seikosha (currently named Seiko Epson), a manufacturing company of Seiko Group. Within one week 100 gold watches had been sold, at a retail price of 450,000 yen (US$1,250) each (at the time, equivalent to the price of a medium-sized car). Essential elements included a Y-type quartz oscillator of 8192 cps, a hybrid integrated circuit, and a phase locked ultra-small stepping motor to turn its hands. According to Seiko, Astron was accurate to ±5 seconds per month or one minute per year, and its battery life was 1 year or longer.
In March 2010, at the BaselWorld watch fair and trade show in Switzerland, Seiko previewed a limited edition new version and related designs of the original Astron watch, commemorating the fortieth anniversary in December 2009 of the debut of the Astron watch.