Timekeepers Club / November 21, 2022

Arnold & Son Nebula 41.5 Gold & Nebula 38 Gold Supernovæ

Built like radiant stars, the Nebula are bursting with light. Created in two case dimensions, they introduce a new colour combination, alternating between grey NAC and 5N red gold, serving to further highlight the striking structure of their skeletonised calibre. The symmetrical elegance of the Nebula collection is entering a new orbit. Arnold & Son shines for its watchmaking skill, its attention to detail and its powerful designs.

Since its creation, Nebula has been a star. Its stellar mechanism, the A&S5201 calibre, is the gravitational force of this collection, giving it its appearance, identity and strength. Redesigned with a movement whose finishes are more advanced than ever, the Nebula collection continues its expansion.


The Nebula case is available in two diameters – 41.5 mm or 38 mm – and is remarkably slim, measuring just 8.73 mm thick. It is crafted from a block of 5N red gold for a limited edition of 88 pieces.


Arranged in a star around the edge of the calibre, the openworked, chamfered and satin-finished bridges create the impression of a watchmaking explosion, as well as a sense of rhythm and control. Positioned at regular intervals, these bridges are identical in shape but different in size and reflect the aesthetic heritage of John Arnold’s chronometers. They also illustrate Arnold & Son’s ‘Manufacture’ expertise.


In space, light never exists alone, but coexists with darkness. A watch inspired by the stars, Nebula thus naturally plays with chiaroscuro. It combines contrasting shades of gold and anthracite grey. The grey is created by a NAC treatment – a galvanic bath fed with metals close to platinum . When applied to the skeletonised main plate, the barrels and the flange, Nebula highlights the relief of its A&S5201 movement. Its construction is clearly legible on various levels, with the bridges in the foreground, the gear train and barrels on the second level, and the main plate behind them.


Viewed from the back, the A&S5201 calibre takes on another dimension. Two large arcs, also treated with NAC, intersect to reveal a second graphic structure, that of the main plate. Highly openworked, it, too, is chamfered and its surface is covered with a signature Arnold & Son pattern known as ‘Rayons de la Gloire’.


Like all the movements used by Arnold & Son, the A&S5201 calibre has been entirely developed, manufactured, decorated, assembled, adjusted and cased-up at the Manufacture in La Chaux-de-Fonds. This calibre draws on a pair of large barrels and an oscillating frequency of 3 Hz, which delivers a 90-hour power reserve. In addition, its depth of 4.18 mm is exceptional for a skeletonised movement, as these types of calibres usually retain a certain thickness in order to compensate for their openworked designs, which typically weaken their structures. Despite this, Arnold & Son’s long Manufacture experience has made it possible to imbue the Nebula’s mechanical latticework with extraordinary finesse.

Technical specifications

Arnold & Son Nebula 41.5 Gold & Nebula 38 Gold

Reference: 1NEAR.S01B.C179A (41.5mm)

Reference: 1NEBR.A03A.C181A (38mm)

Limited edition of 88 pieces


  • Material: 18-carat red gold (5N)
  • Diameter: 41.50 mm or 38 mm
  • Thickness: 8.73 mm
  • Crystal: domed sapphire, anti-reflective coating on both sides
  • Case back: sapphire crystal, anti-reflective coating
  • Water-resistant to 30 metres/100 feet

Dial and hands

  • Anthracite flange, golden appliques


  • Calibre A&S5201
  • Manual winding movement
  • Number of jewels: 24
  • Diameter: 31.10 mm
  • Thickness: 4.18 mm
  • Frequency: 21,600 vph (3 Hz)
  • Power reserve of 90 hours


  • main plate: NAC-treated, ‘Rayons de la Gloire’ guilloché
  • barrel covers: NAC-treated and sunray-brushed
  • bridges: 18-carat red gold (5N), polished angles and satin-finished surfaces
  • balance wheel: rhodium-plated
  • wheels: circular-grained and bevelled
  • screws: bevelled and mirror-polished heads

Strap and buckle

  • Grey hand-stitched alligator leather strap
  • 18-carat red gold (5N) pin buckle


  • CHF 30,900 including taxes
  • CHF 28,600 including taxes

For more information, please visit


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