Christiaan van der Klaauw skeletonizes its Planetarium for six platinum watches

Christiaan van der Klaauw has unveiled the Planetarium Skeleton Platinum, an openworked version of the Dutch manufacture's signature astronomical complication, limited to six individually numbered pieces. The watch is presented in a 40mm platinum case with sapphire crystals on both sides and is priced at EUR 86,000 excluding VAT. It borrows its skeletonized architecture from the earlier unique Planetarium Julie.

The defining feature is the transparent sapphire dial, which exposes most of the astronomical module's mechanical structure rather than concealing it behind a solid disc. Blued Roman numerals run from 9 to 3 across the upper section of the dial, described by the maker as "above the horizon," providing the only conventional time reference on an otherwise open face.

At 6 o'clock, the Planetarium module displays the real-time orbits of six planets around a central Sun: Mercury, Venus, Earth, Mars, Jupiter and Saturn, each following its own calculated path. Mercury completes its orbit in 87.97 days and Venus in 224.70 days, against Earth's 365.24 days, Mars's 686.98 days, Jupiter's 11.86 years and Saturn's 29.46 years.

What the skeletonization changes

The custom bridges are shaped like the Christiaan van der Klaauw logo itself, a sun with twelve radiating claws, and in this version those forms become working parts of the movement rather than decoration. They extend around the Planetarium module and expose more of the gearing beneath the sapphire dial than any prior interpretation of the complication.

Bridges and plate are rhodium-plated for a consistent metallic tone against the transparent dial, and the blue planetary rings keep the effect used since the original 2000 Planetarium: color runs from bright light blue near the Sun to progressively darker shades toward the outer orbits, representing sunlight weakening with distance.

A subdial at 12 o'clock adds date and month indications alongside central hours and minutes, all shown with blued hands. Water resistance is rated to 50 meters, modest for the case but standard for a dress watch built around a visible astronomical module rather than sport use.

The movement behind the display

The watch runs on the CKM-01, an automatic manufacture caliber developed for Christiaan van der Klaauw with UhrTeil AG, the movement house founded by Andreas Strehler. It is the same base used in the Grand Planetarium Eccentric, running at 21,600 vibrations per hour with a free-sprung hairspring, a variable-inertia balance wheel and a 60-hour power reserve.

Finishing includes circular decoration on the star-shaped bridges, frosted star decoration, perlage on the main plate and rhodium plating throughout. The rotor is skeletonized, plated in rose gold and shaped as the CVDK logo, with a rhodium-plated tungsten weight to keep the winding efficient despite the open design.

The case retains the brand's familiar language: an onion-shaped crown and straight lugs, both recognizable across the Planetarium line since it began. The watch is fitted to an FKM sailcloth strap and closes with a stainless-steel folding clasp bearing a platinum CVDK logo, the only steel component on an otherwise platinum and rhodium piece.

Why the Planetarium matters to this maker

Christiaan van der Klaauw has built mechanical astronomical watches since the 1990s, and the Planetarium is the complication that defines the manufacture. The first Planetarium wristwatch arrived in 1999 and carried what the brand describes as the world's smallest mechanical planetarium at the time, a claim it has carried across every subsequent version of the module.

The complication has since been reinterpreted repeatedly, including in the Grand Planetarium Eccentric and the unique Planetarium Julie, whose openworked case construction this new Platinum edition adopts directly. Each version has kept the same orbital logic while changing how much of the mechanism a wearer can actually see, and the Skeleton pushes that furthest yet.

Astronomical watchmaking of this kind is a narrow corner of independent high horology, where a handful of manufactures build orbital or celestial displays as their signature rather than as a one-off exercise for a single collection.

We have tracked how smaller manufactures compete against the major maisons in our guide to the best luxury watch brands, and Christiaan van der Klaauw's specialization in planetary mechanisms is the kind of narrow expertise that guide looks for. The maison's output stays small by design: six numbered pieces here, a single unique piece with the Julie before it.

The complication is alongside the perpetual calendars, tourbillons and minute repeaters we cover in our guide to watch complications, though a planetarium module remains rarer than any of those in serial production.

Six pieces at EUR 86,000 excluding VAT puts the Planetarium Skeleton Platinum firmly in collector territory rather than a retail proposition aimed at a broader audience, and the onion crown and straight lugs place it within our broader survey of watch case shapes and the design choices that separate one maker's language from another's.

Christiaan van der Klaauw has not stated whether the Planetarium Skeleton Platinum will be followed by variations in other case metals, as has happened with earlier Planetarium references. Full technical detail and ordering information are directed to the brand's own site, and the EUR 86,000 price excludes VAT, which will add to the final cost depending on the buyer's jurisdiction.