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).^[1] Essential elements included a XY-type quartz oscillator of 8192 Hz (8192 = 2¹³), 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.^[2]

In March 2010, at the Baselworld watch fair and trade show in Switzerland, Seiko previewed a limited edition new version of the watch and related designs of the original Astron watch, commemorating the fortieth anniversary in December 2009 of the debut of the Astron watch.^[3]

Seiko used the "Astron" trademark again as "Seiko Astron" when it released a satellite radio-wave solar-powered wristwatch using GPS satellites in 2012.^[4]

• "IEEE History Center: Electronic Quartz Wristwatch, 1969". IEEE.
• "Seiko Quartz Astron 35SQ December 1969: The quartz watch that revolutionized horological history". Seiko Epson. Archived from the original on 2012-03-10. Retrieved 2012-07-22.
• "The Watch That Changed Horological History" (PDF). Seiko Epson. Archived from the original (PDF) on March 31, 2010. (alternate version Archived 2022-03-16 at the Wayback Machine)