Spacegraf Heure Sidérale Tourbillon Volant Limited Edition

The Architect

ExpertOct 22, 2026

76

The Yema Spacegraf Heure Sidérale Tourbillon Volant occupies a position of considerable horological ambition within a lineage that has, for much of its commercial history, operated at modest price registers. Yema's predecessors — the utilitarian Spationaute and various Sous-Marine iterations — did not prepare the market for a flying tourbillon regulated to sidereal time, a complication whose constituency is measurably small even among the technically literate. Concordantly, the decision to engage Calibre Manufacture Morteau for the CMM.32 represents a defensible strategy for a manufacture lacking the vertical integration of its Swiss counterparts: the movement delivers 105 hours of power reserve at manual wind, a figure that elevates this caliber above category norms with mathematical clarity. The titanium case at 42mm and 12.15mm thickness achieves a proportion that acknowledges wearability without fully resolving the tension between complication depth and case discipline. The dial architecture, structured to present sidereal hour information alongside conventional indications, reflects considered hierarchical design — the probability of visual coherence at this level of information density being maintained is not trivial, and Yema manages it with notable success. The leather strap, however, represents the iteration's least resolved element: adequate as a functional carrier, it introduces no distinction commensurate with the movement beneath it. As you undoubtedly gather, the value equation at $15,228 is defensible but not self-evident — the inevitability of limited provenance moderating what remains a significant ask for the Yema marque.