The Seiko Astron

The Astron came out of about ten years of work at Suwa Seikosha, the Seiko company now called Seiko Epson, which began its 59A project in 1959.^1, 5, 6

The way ran through larger quartz machines: a broadcasting clock in 1958, a marine chronometer entered at Neuchâtel in 1963, the timers of the 1964 Tokyo Olympics, and a wristwatch prototype entered at Neuchâtel in 1967.^1, 2

It went on sale in Tokyo on 25 December 1969 as the Seiko Quartz-Astron 35SQ, by Seiko’s and the IEEE’s dates; a CEH researcher’s memoir gives 26 December.^1, 2, 7

Seiko and the IEEE describe it as the first quartz wristwatch, and the Japan Society of Mechanical Engineers as the first quartz-type wristwatch; Swiss prototypes had run in 1967, so the claim rests on its being the first sold.^{1, 2, 3, 8}

It kept time with a quartz crystal vibrating 8,192 times a second, divided down by an electronic circuit to drive a small stepping motor that turned the hands.^1, 9, 10

Sources describe the crystal and circuit differently: the IEEE and the Deutsches Uhrenmuseum record an XY-cut crystal and a hybrid integrated circuit, while Seiko’s museum describes a tuning-fork crystal in a vacuum capsule and a CMOS chip of its own.^1, 6, 9

Seiko gives its accuracy as within five seconds a month, about a minute a year, with a battery lasting more than a year.^1, 12

It was priced at 450,000 yen, and the IEEE records that a hundred of the 18-carat gold watches sold in the first week. The Deutsches Uhrenmuseum’s record says only a hundred were sold, so how many were made is not settled here.^{1, 2, 4, 12}

Seiko says it disclosed much of the patent portfolio built up for the Astron, and that its competitors then adopted the Seiko method.²

The IEEE gave it an Innovation Recognition Award in 2002 and named it an IEEE Milestone in 2004; the plaque was dedicated on 25 November 2004 at the Seiko Institute of Horology in Tokyo.^1, 2

On 7 August 2014 the Japan Society of Mechanical Engineers designated it, with Seiko’s Laurel of 1913 and an early Grand Seiko, as Mechanical Engineering Heritage No. 66.^3, 6

The Seiko Museum Ginza exhibits the designated Astron, and the Deutsches Uhrenmuseum in Furtwangen holds a watch and a 35A movement, No. 00234.^3, 4, 9

Wikipedia’s account says Seiko reused the Astron name in 2012 for a solar watch that sets itself from GPS satellites.¹²