TISSOT Navigator Seastar T12 ref.44566-2 cal.788 / 24-Hour World Timer

Every vintage mechanical wristwatch was designed with a purpose of its own: some put style first, others function.

This rare model, the Tissot Navigator T12, has both.

Where many models put a day-and-night function on the bezel, this one cleverly reflects how well a 24-hour display and a two-tone dial work together for exactly that purpose.

The upper half of the dial is a bright tan representing 6am to 6pm, and the greyish-brown lower half represents the dark hours from 6pm to 6am.

It is sunray finished, showing a range of expressions as the angle changes.

The movement is the automatic Cal. Tissot 788.

An unhurried low beat of 18,000 bph.

The hour hand makes one revolution in 24 hours rather than twelve.

The caseback is a screw back struck with the Spanish galleon that is the Seastar's emblem.

Inside the caseback is a diving helmet marking, indicating an EPSA Super Compressor case.

It has a world time function, allowing the time in any country to be compared with local time.

Focus on the time axis — the reference city of the wearer's own time zone — and the time in your target country can be read from a quadrant divided into 24 sectors.

Which is to say: for any pilots reading this page, there could hardly be a better watch.

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