Focus #7 – THE FAR SIDE OF THE MOON DISC

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At the heart of the Orion series, one piece stands out for its complexity and ambition: the Moon disc. Designed in partnership with the AJS Production workshop, this tiny circular surface is the result of two years of research and experimentation. A unique piece, at the intersection of watchmaking craftsmanship and revolutionary laser technology.

As the Orion series approaches its assembly, production of the models is now nearing completion. All components have been validated; only the Moon disk remains in the final stages of development—like the guest of honor who arrives last. This is an opportunity for us to share with you a behind-the-scenes look at this unique manufacturing process.

Super-LumiNova®: impossible to work with?

The origin of luminescence in watchmaking and the challenge it represents

To understand the challenge posed by this piece, we must look at its composition—and in particular the material that produces its luminescence.

The problem? Super-LumiNova® comes in the form of a powder or viscous paste when mixed with a binder. This particular consistency makes it very difficult to apply evenly, especially when very fine levels of detail are required. Any attempt at engraving or deposition requires extreme precision: the material is sensitive to heat, pressure, and solvents, and does not tolerate rework or retouching.

Super-LumiNova® is a Swiss photoluminescent pigment developed in the 1990s by RC Tritec AG as a replacement for radium and then tritium, two radioactive substances formerly used in watchmaking. This material is based on strontium-doped aluminum oxides, capable of storing natural or artificial light and releasing it in the dark, without any health risks.

The first reaction of the AJS Production workshop, when we contacted them two years ago, was naturally to explain the technical infeasibility of such a project. But the idea gained ground, and the R&D team of this brilliant Swiss laboratory focused more rigorously on a central challenge in watchmaking: how to work, with extreme precision, a material as viscous and unstable as Super-LumiNova?

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THE LUMINOVA STICKER TRICK

Transforming an unstable material into a homogeneous luminescent base in the form of a sticker

The first idea was to transform Super-LumiNova into a thin, self-adhesive layer, to be applied directly to a brass disc—a solution recently implemented in the watch industry to overcome the limitations of manual deposition on flat surfaces.

Super-LumiNova stickers are thin, pre-cut films of luminescent material, in BGW9, applied like an adhesive film to complex surfaces. Designed to overcome the limitations of manual deposition, they allow a more uniform and precise application, while better resisting engraving or machining steps.

In our case, this sticker was used as the first layer of the Moon disc, providing a stable and luminous base on which to work. Each Super-LumiNova sticker is custom-made, then meticulously applied by hand to a brass disc by a master watchmaker.

At this point, we have a 0.28 mm thick brass disc, covered with a Super-LumiNova BGW9 or C1 sticker. This surface offers a perfectly smooth and homogeneous luminescence, but is still too sensitive to be directly worked or engraved.

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APPLYING LAYERS OF PAINT

Create the base of the sky without turning off the light

The next idea was to cover this first layer with several successive applications of ultra-thin paint. The pigments used—specially formulated watchmaking acrylics—are chosen for their ability to interact with light without smothering it. Some layers are slightly translucent, others more opaque, creating areas of shadow or contrast.

White pigments diffuse light more softly, while deep blue hues add density and nuance to the night sky . Each application is carried out by micro-spraying, using a high-precision paint gun.

This step, carried out entirely by hand, is one of the most delicate in the process . Each layer of paint must be perfectly uniform: the slightest false movement, an excess of material or a simple overflow can compromise the entire rendering. In this case, it is impossible to correct — you have to throw the piece must be discarded and the process restarted from scratch.

At the end of this phase, the disc reaches approximately 0.35 mm in thickness. The Super-LumiNova is no longer visible on the surface, but it is waiting to be revealed , layer by layer, by the beam of a laser. This is what we will see in the last step.

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BURNING THE PAINT WITH LIGHT

When technology gives shape to matter

To dig into the material with extreme precision, the AJS team used a technology that is still relatively uncommon in watchmaking: the femtosecond laser.

This type of laser, also called a “femto laser,” emits ultra-short pulses of light—of the order of 10⁻¹⁵ seconds—that ablates material without causing thermal damage or microcracks. Developed in the 1990s, this technology has its origins in the work of physicist Gérard Mourou and his doctoral student Donna Strickland, both awarded the Nobel Prize in Physics in 2018. Initially designed for microsurgery and precision optics, it has been adapted for industry to engrave sensitive materials… and has now reached the world of watchmaking.

In the case of our lunar disk, each impact removes material to the nearest micron (0.001 mm), revealing the luminescent areas buried under the layers of paint . This method allows relief to be created without adding thickness —more of an engraving of light than a sculpture. The use of the femto laser thus made it possible to draw each crater, each star, with extreme precision, by finely adjusting the depth and intensity of the engraving.

This experimental process is particularly complex to master: removing too much material creates hollows that are too deep; too little, and the Moon remains flat, lifeless. The interaction between the painted layers and the photoluminescent pigment is also unpredictable: some areas burn too quickly, others reflect light unevenly. It took producing and adjusting numerous series of prototypes to find the perfect balance.

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THE RESULT: A FRAGMENT OF THE COSMOS

A vivid reading of the sky on a 6mm surface

The final rendering of the Orion series Moon disc lives up to the initial ambitions: a piece of unprecedented precision in contemporary watchmaking. Each star has been engraved according to its actual position in the sky , within a radius covering the entire constellation of Orion. and its neighbors — Taurus, Gemini, Canis Major, Monoceros… The celestial vault thus represented follows an exact map, faithful to within 0.001 mm.

Thanks to the femtosecond laser, only certain stars light up in the darkness : the brightest, chosen according to their actual magnitude, creating a subtle and realistic reading of the night sky.

The Moon itself presents a striking relief. Its craters are delicately carved into the material, with soft, irregular edges, giving an almost tactile depth to the disk . The high areas remain in shadow, while the hollows allow a discreet blue glow to shine through, as if it glowed from its own core.

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A piece born from know-how, light, and your support

The photographs you discover here illustrate this patient work: the masking of the discs one by one, the spraying of the pigment layers, the gradient tests, and finally the assembly of each piece, by hand , to avoid the slightest micro-scratch. This miniature piece thus becomes a fragment of the cosmos in its own right, condensed into a few tenths of a millimeter.

This disc doesn't just indicate a lunar phase: it tells a story. That of a Swiss workshop pushing the boundaries of miniaturization, and of an independent watchmaking project exploring new frontiers.

We are happy and proud to share this story with you, and we sincerely thank you for making it possible. Your support during the Kickstarter campaign helped fund the research and development of this disc, and launched the production of the first 800 pieces . This moon will soon find its place on your wrist—thank you for your trust.