Variants of the Quartz-Astron, world's first quartz watch
Nov 17, 2020 12:23:50 GMT -8
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Post by theseikoguy on Nov 17, 2020 12:23:50 GMT -8
The Seiko Quartz-Astron debuted in Tokyo stores on December 25, 1969 as the world’s first commercial quartz wristwatch, with a luxurious 18-karat solid gold case, hand carved by skilled craftsmen.
While the margin of error for standard mechanical watches was around ±20 seconds per day, the Astron was 100 times better with an incredible accuracy of ±0.2 seconds per day, or ±5 seconds per month.
Suitable integrated circuits were not available yet, so they had to rely on a hybrid circuit composed of many transistors, resistors and condensers, hand-soldered at 128 points. Doing this work by hand, on a movement so small, should have been incredibly difficult and required high skills, and this is probably the main reason why they only produced very few pieces per month.
The very first version, produced from late 1969 to mid 1970 in few hundred pieces, was characterized by the Quartz-Astron writing under the Seiko logo.
A short time later, two variants were introduced to the market, both produced from January 1970 and with the same solid gold case.
In 1971, months after ending the production of all the three gold cased watches, Seiko introduced two new models with a stainless steel case.
Quartz-Astron 35SQ (35-9000, first quartz watch)
Produced from the end of 1969 (the earliest serials that I saw date back to November 1969), until the middle of 1970. It debuted in Tokyo stores on December 25, 1969.
Solid 18-karat gold case, “Quartz-Astron” writing under the Seiko logo at 12 o’clock.
Quartz-Astron 35SQC (35-9000, first version with a date window)
Produced from early 1970, the 18-karat gold case appears to be the same as the first model, except for the gold bezel, which is slightly different between the two.
No “Quartz-Astron” written on the dial at 12 o’clock, replaced by the Quartz logo at 6 o’clock.
“Alternative” Quartz-Astron 35SQ (35-9000)
Produced from early 1970, 18-karat gold case like the previous models.
Quartz logo at 6 o’clock like the version with date window.
Looking closely at the gold Quartz-Astron 35SQ and the date version 35SQC, the main part of the case appears to be exactly the same, while the gold bezel is clearly different between the two models.
My guess is that it wasn’t just a stylistic choice. The bezel of the date model seems to make the watch case slightly taller, and it was probably necessary in order to fit the date version of the caliber, slightly thicker than the non-date 35A.
Quartz-Astron 35SQ in stainless steel (35-9010)
Introduced in 1971 (based on the earliest serial numbers, production seems to have started at the end of 1970). Stainless steel case, Quartz logo at 6 o’clock.
Quartz-Astron 35SQC in stainless steel (3502-9010, version with date)
Introduced in 1971 together with the version without date. Stainless steel case and Quartz logo at 6 o’clock, like the model without date.
While the gold cased models had a hybrid circuit, the movement of the stainless steel models hides a CMOS integrated circuit, developed by Daini Seikosha in collaboration with Intersil. The frequency has doubled to 16,384 Hz from the previous 8,192 Hz, which affects the accuracy of the watch, further improved to ± 0.1 seconds per day and ± 3 seconds per month.
While the margin of error for standard mechanical watches was around ±20 seconds per day, the Astron was 100 times better with an incredible accuracy of ±0.2 seconds per day, or ±5 seconds per month.
Suitable integrated circuits were not available yet, so they had to rely on a hybrid circuit composed of many transistors, resistors and condensers, hand-soldered at 128 points. Doing this work by hand, on a movement so small, should have been incredibly difficult and required high skills, and this is probably the main reason why they only produced very few pieces per month.
The very first version, produced from late 1969 to mid 1970 in few hundred pieces, was characterized by the Quartz-Astron writing under the Seiko logo.
A short time later, two variants were introduced to the market, both produced from January 1970 and with the same solid gold case.
In 1971, months after ending the production of all the three gold cased watches, Seiko introduced two new models with a stainless steel case.
Quartz-Astron 35SQ (35-9000, first quartz watch)
Produced from the end of 1969 (the earliest serials that I saw date back to November 1969), until the middle of 1970. It debuted in Tokyo stores on December 25, 1969.
Solid 18-karat gold case, “Quartz-Astron” writing under the Seiko logo at 12 o’clock.
Quartz-Astron 35SQC (35-9000, first version with a date window)
Produced from early 1970, the 18-karat gold case appears to be the same as the first model, except for the gold bezel, which is slightly different between the two.
No “Quartz-Astron” written on the dial at 12 o’clock, replaced by the Quartz logo at 6 o’clock.
“Alternative” Quartz-Astron 35SQ (35-9000)
Produced from early 1970, 18-karat gold case like the previous models.
Quartz logo at 6 o’clock like the version with date window.
Looking closely at the gold Quartz-Astron 35SQ and the date version 35SQC, the main part of the case appears to be exactly the same, while the gold bezel is clearly different between the two models.
My guess is that it wasn’t just a stylistic choice. The bezel of the date model seems to make the watch case slightly taller, and it was probably necessary in order to fit the date version of the caliber, slightly thicker than the non-date 35A.
Quartz-Astron 35SQ in stainless steel (35-9010)
Introduced in 1971 (based on the earliest serial numbers, production seems to have started at the end of 1970). Stainless steel case, Quartz logo at 6 o’clock.
Quartz-Astron 35SQC in stainless steel (3502-9010, version with date)
Introduced in 1971 together with the version without date. Stainless steel case and Quartz logo at 6 o’clock, like the model without date.
While the gold cased models had a hybrid circuit, the movement of the stainless steel models hides a CMOS integrated circuit, developed by Daini Seikosha in collaboration with Intersil. The frequency has doubled to 16,384 Hz from the previous 8,192 Hz, which affects the accuracy of the watch, further improved to ± 0.1 seconds per day and ± 3 seconds per month.
