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Seiko’s New Prospex ‘Astrolabe’ Save the Ocean SLA065J1 is Inspired by Naval Exploration

Seiko Prospex Astrolabe Save the Ocean Limited Edition SLA065

Seiko have launched a new limited edition diving watch inspired by the first ever Japanese dive watch from 1965. On the surface, it seems like there isn’t much to the launch, yet another retro re-interpretation from Seiko. However, take a closer and there’s actually a lot going on, starting with the watch’s name: the Seiko Prospex Astrolabe Save the Ocean SLA065J1 Limited Edition.

An astrolabe is a piece of historical equipment used by sailors to navigate across the seas using measurements taken from the sun and stars. It is in many ways one of the most important pieces of technology in human history (along with the chronometer, of course) allowing for global exploration and trade.

Seiko Prospex Astrolabe Save the Ocean Limited Edition SLA065

What that means for the new Prospex is a dial which features an engraved emulation of an astrolabe display. While I have no idea how to read an astrolabe. Although it does bear some similarities to the PADI pattern from models like the King Sumo or even the Frederique Constant Highlife Worldtimer. However, all three are basically different interpretations of the same thing, the globe, hence the similarities. It also does nothing to detract from the fact the Astrolabe is the trippiest, almost like a magic eye image with its criss-crossing lines.

The whole pattern is presented in a deep ocean blue colour punctuated by oversize rectangular indexes coated with lume. It all fits within the aesthetic of a 60s diver very well, which makes sense because it’s based on a watch from the 60s after all. The intriguing dial is contained within a 41.3mm diameter stainless steel case with brushed finishing.

Seiko Prospex Astrolabe Save the Ocean Limited Edition SLA065

Although, most interestingly, the unidirectional rotating bezel has a different finish, Zaratsu polishing. Zaratsu polishing (or black polishing outside of Japan) is a specialist Japanese finish commonly used by Grand Seiko and a few other Japanese watchmakers.

I can’t think of another Prospex model that uses this high level of finishing, although I’m willing to accept that somewhere in Seiko’s enormous catalogue there may be one or two others, probably with the letters LX after them. Regardless, it’s pretty special.

Seiko Prospex Astrolabe Save the Ocean Limited Edition SLA065

Inside, the Seiko Prospex Astrolabe Save the Ocean Limited Edition houses one of their most advanced calibres. It’s the 8L35, an automatic movement with a 50-hour power reserve and an accuracy of +15/-10 seconds per day. However, its biggest advantage is difficult to quantify because it was specially designed with durability in mind in order to withstand the rigorous life of a professional diving watch.

Seiko Prospex Astrolabe Save the Ocean Limited Edition SLA065

Between the level of finishing, the movement, the unique dial and the fact it’s limited to 1,300 pieces, the Prospex Astrolabe isn’t quite as accessible as Seiko is usually lauded for. Instead, it has a price of £2,540, nowhere near Grand Seiko prices but still not cheap.

Fortunately, as part of the Save the Ocean series, sales of the Astrolabe will help to fund global ocean conservation and debris removal. This is, in my opinion, an excellent example of watchmaking as it should be. On the surface it’s relatively unobtrusive and subtle but the more you look at and study it, the more details come to light.

Price & Specs:

  • Model: Seiko Prospex ‘Astrolabe’ Save the Ocean
  • Ref: SLA065J1
  • Case/dial: 41.3mm diameter x 13.1mm thickness, stainless steel case, blue astrolabe pattern dial
  • Water resistance: 200m (20 bar)
  • Movement: Seiko calibre 8L35, in-house, automatic, 26 jewels
  • Frequency: 28,800 vph (4 Hz)
  • Power reserve: 50h
  • Functions: Hours, minutes, hacking seconds, date
  • Strap: Blue silicone with stainless steel pin buckle
  • Price/availability: £2,540, limited edition of 1,300 pieces

About the author

Michael Sonsino

As Junior Content Producer for Oracle Time, Michael needs an eye for detail, which makes it a good thing that his twin joys in life are miniatures and watches. While a relative newcomer to the magazine, he's nonetheless a lifelong fan of fine timepieces, especially those of a more historic nature - if it has a twist of Art Deco, all the better.

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