Yema Turns to Sidereal Time for Its 2026 Spacegraf Flying Tourbillon

Yema’s latest Millésime watch takes the brand’s recent complication work in a more astronomical direction.

The Spacegraf Heure Sidérale Tourbillon Volant Millésime 2026 combines a flying tourbillon with a celestial display that tracks sidereal time, giving the watch a technical character distinct from last year’s Superman Tourbillon Millésime CMM.31.

It’s also a reminder that French watchmaking has long had one eye on the sky, particularly in Besançon, where the observatory founded in 1878 helped local watchmakers regulate their timepieces through astronomical observation.

At a glance

• Yema has introduced the Spacegraf Heure Sidérale Tourbillon Volant Millésime 2026 as a 150-piece limited edition.
• The watch pairs a flying tourbillon at 6 o’clock with a rotating celestial disc that completes one turn every sidereal day.
• It is priced at EUR 14,500 and uses Yema’s French-made calibre manufacture CMM.32.

A Spacegraf built around the night sky

The Spacegraf name is doing more than cosmetic work here.

Rather than placing a tourbillon inside a familiar sports-watch framework, Yema has built the dial around an astronomical display, with the celestial disc at 12 o’clock and the flying tourbillon directly opposite at 6 o’clock.

The celestial disc rotates once every sidereal day, which lasts 23 hours, 56 minutes and 4 seconds.

That makes it different from a standard 24-hour indication, because sidereal time measures Earth’s rotation relative to distant stars rather than the Sun.

The result is a complication with a specific astronomical reference point, not simply a decorative star chart.

Time is read by the central hands, while a small hand mounted on the tourbillon cage indicates running seconds.

Grade 5 titanium and a dark luminous dial

The watch is housed in a 42mm Grade 5 titanium case measuring 12.15mm thick.

Yema uses a curved case with contrasting brushed finishes and polished accents, while the sharper geometry of the lugs gives the watch a more technical stance.

A double-domed sapphire crystal sits above the dial, and a sapphire caseback opens the movement side.

The fluted crown at 3 o’clock carries the Yema logo, and the case is rated to 100 metres of water resistance.

The dial is black, sandblasted, and coated with black PVD, which gives the astronomical elements a dark stage rather than a bright observatory-style treatment.

A circular-brushed minutes track frames the display, with double-digit numerals marking the five-minute intervals.

Yema also leans heavily into lume, with the hands, hour-marker ring, minutes track, celestial aperture frame, and graduated tourbillon frame glowing in dark blue.

Some of those elements are made from solid Super-LumiNova blocks, a detail that should make the dial architecture more physical in low light.

The CMM.32 movement from Morteau

Inside is the calibre manufacture CMM.32, produced in Morteau, France.

The movement builds on the construction used in Yema’s previous tourbillon watches and was developed with watchmaker Olivier Mory.

A large barrel provides a stated power reserve of 105 hours.

Yema says the movement is designed to withstand shocks, vibrations and accelerations of up to 5,000 Gs in all directions.

Viewed through the sapphire caseback, the movement is finished in blue and decorated with a celestial map.

The barrel cover uses a different shade of blue and represents a world map, linking the movement decoration back to the watch’s astronomical theme.

Details & Specifications

The Spacegraf Heure Sidérale Tourbillon Volant Millésime 2026 feels aimed at collectors who are interested in Yema’s move beyond tool-watch territory and into more elaborate French-made complications.

Its appeal rests less on spectacle alone than on the way the flying tourbillon, sidereal display and Besançon astronomical reference come together in a watch that feels unusually specific within the brand’s modern catalogue.