A&S Nebula 38 Steel

An auspicious encounter between distinctive aesthetic flair and rare technical skill, the Nebula 38 Steel fully expresses Arnold & Son’s identity as a Swiss watchmaker with English roots. Its openworked movement ties it to the great tradition of British watchmaking, while its design methods and finishes reflect the very best of Swiss quality. Lastly, its composition places it in a rare category: that of harmonious yet striking skeleton watches.

The Nebula 38 is now available in steel. Following the launch of a red-gold version, the house’s iconic watch is now entering new territory where ultra-technical watchmaking is encased in an understated exterior, with a diameter rarely seen in this category and exemplary slimness.

A&S Nebula 38 Steel

Identity and style

Semantically, the name ‘Nebula’ was chosen because the sculptural movement driving this timepiece evokes an inverted star that has exploded in an ideal orderly fashion, i.e. with all the bridges converging from the outside of the dial towards the centre, like perfectly symmetrical rays. In terms of complications, the Nebula 38 belongs to the family of three-handed watches indicating the hours, minutes and off-centred small seconds. Lastly, in terms of complexity, this timepiece constitutes one of the most graphically striking, high-impact and original skeleton watches.

The Nebula 38 pushes mechanistic aesthetics to such an extreme that its movement has become its very identity. The dial is reduced to a black lacquered flange, while the calibre mesmerises the eye with its arrangement, layers and curves, its juxtaposed materials and play on solids and hollows. Here, the A&S5101 calibre is the dominant orator, speaking in the style of John Arnold. By continually drawing on the intellectual and aesthetic heritage of the genius watchmaker from whom it takes its name, Arnold & Son conveys a message based on technical skill, coupled with balance, measurements and proportions.

A&S Nebula 38 Steel

Openworked structure

The structure of the A&S5101 calibre is based on carefully considered symmetry. Seven bridges span the four axes that cross the Nebula 38, creating a sense of visual balance. Meanwhile, the proportions are communicated by the dimensions of the steel case: a diameter of 38 mm for a thickness of 8.91 mm, with a domed sapphire crystal on the dial side and a flat sapphire crystal on the case back.

On the dial side, the Nebula 38 enumerates its components explicitly, almost didactically: a double barrel bridge, crown bridge, balance bridge, geartrain bridges…everything is clear, visible and structured. While all these bridges dialogue with each other on opposing axes within the movement, the functional elements also adhere to this mirrored design. The small-seconds function at 7 o’clock, for example, is twinned with the balance. While technically different, these two blocks adopt similar shapes to perfect the movement’s sense of equilibrium. The harmony is plain to see, as all the bridges, plates and solid components are openworked.

A&S Nebula 38 Steel

Order and beauty

This construction was far from easy to devise, however. Arranging the structures of a skeleton movement in a ring facing inwards is an utterly unique approach. Furthermore, to maintain the sense of symmetry, Arnold & Son moved the winding mechanism linked to the crown stem to the case back, giving it an unusual position that is entirely justified for the overall aesthetic coherence it procures. In spite of this, the Nebula 38 was designed with practicality in mind, as it presents a 90-hour power reserve that is rare for skeleton models.

The characteristic Arnold & Son style shines through in the masterful play on contrasting surfaces adorning the Nebula 38. The house has used a variety of colours, finishes and levels to ward off any risk of illegibility. The bridges are thus all the same height on the dial side, while on the case-back side, a large sapphire crystal reveals a mainplate that has been openworked to the extreme. Its design features several criss-crossing arcs, with intersecting circles and ellipses that are reminiscent of a Gothic cathedral’s vault.

Ergonomic yet technical, aesthetic yet legible, and expressive yet slim, the Nebula 38 Steel is a truly unique timepiece. Once again, Arnold & Son is expressing its desire to establish exceptional watchmaking in limited quantities at fair prices.


Knowing the time determines your location. This fact has been proven throughout the history of high-sea navigation thanks to its close ties to watchmaking. Dual time zones are central to Arnold & Son’s history, with the marine chronometers of yesterday and today’s two iconic models, the DTE and DBG Skeleton.

Before the advent of marine chronometers in the 18th century, a captain was able to determine the position of his ship on the north-south axis, i.e. its latitude. However, as the Earth turns on an east-west axis, the traditional points of reference (the sun and stars) could not be used to determine its longitude. The problem was solved with watchmaking. A highly accurate clock was taken on board and kept at the time at the starting point. As the ship advanced, the captain measured the time specific to its position by looking for noon. The difference between the local and original times allowed him to assess progress across the seas. The marine chronometer was born.

In the wake of these inventions, John Arnold (1736-1799) proved himself to be one of the most inventive watchmakers of his generation and of the golden age of timekeeping. Indeed, Arnold worked ceaselessly to perfect, miniaturise and enhance the reliability of his marine chronometers. By helping to popularise chronometer technology, his name became indissociable from the history of maritime navigation and the conquests made possible by the very concept of dual time.


To pay homage to its founder, Arnold & Son has always treated dual time with a particular degree of sophistication and accuracy. Instead of the traditional GMT system where an hour hand in the centre indicates the secondary hour, Arnold & Son chose to give each of the two time zones a dedicated regulating organ to recall the duality of the measurement methods – one horological, the other astronomical – used aboard English frigates.


DTE, Double Tourbillon Escapement

The DTE model combines Dual Time with two tourbillons. In the A&S8513 calibre, they are connected by a common motor organ, a pair of barrels providing a running time of 90 hours. These barrels then supply each of the separate gear trains, which each end in a tourbillon. These independent components indicate the hours and minutes and ensure an exceptional level of timekeeping.

The symmetry of the indications – an Arnold & Son signature – is particularly evident on this DTE model. The two time zones – local time in Roman numerals and reference time in Arabic numerals – are superimposed at 12 o’clock and 6 o’clock respectively. The tourbillons mirror each other at 3 o’clock and 9 o’clock and appear to float in mid-air thanks to their hand-chamfered 18-carat gold bridges. The mainplate on the dial side presents a vertical Côtes de Genève finish. To add to the balance of this timepiece, the crowns are positioned at 2 o’clock and 8 o’clock, allowing each time zone to be adjusted independently.

The DTE is housed in an 18-carat red gold or white gold case with a sapphire crystal case back that reveals the entirely decorated movement, the mainplate with its radiating Côtes de Genève finish, and the circular satin-finished wheels.


DBG Skeleton, Double Balance GMT

Meanwhile the DBG Skeleton model uses two traditional regulating organs. They have been constructed using the same principle of independence as the DTE but taken even further. The A&S1309 calibre has two complete and independent kinetic chains. Each time zone has its own barrel, gear train, escapement and balance-spring assembly. They are positioned side by side on the same mainplate. They share a central seconds hand and a day/night indicator. This indicator, located at 12 o’clock, is fitted with two concentric hands, each referring to one of the time zones of this one-of-a-kind timepiece.

Particular attention has been paid to the time display. A tinted sapphire disc has been selected for each of the dials. The local time zone is indicated by hands with a skeletonised tip and Roman numerals, while the reference time zone is distinguished by solid-tip hands and Arabic numerals. The day/night indicator at 12 o’clock uses the same hand design to differentiate between the time zones. To add to the symmetry of the DBG Skeleton, two crowns sit opposite each other at 3 o’clock and 9 o’clock. This makes it possible to adjust each time zone independently, while the double barrel is wound simply by the crown at 3 o’clock.

Housed in a rose gold case measuring 44 mm in diameter, the entirely skeletonised A&S1309 manufacture calibre is meticulously worked, with chamfered and polished rhodium-finished bridges complete with satin-finished surfaces. On the back, the mainplate reveals a rhodium treatment decorated with Côtes de Genève, while the wheels are satin-finished to add a noticeable contrast.

A&S DGB Skeleton Calibre


While most GMT-style watches have two distinct hour indications and shared minutes, the Arnold & Son DTE and DBG Skeleton each have two distinct sets of minute hands. The local time hand can be adjusted to the nearest minute and is indexed to the other minute hand for the point of origin. The latter hand can also be set separately in quarter-hour intervals to accurately adjust to certain time zones. This is because some areas of the world do not use the same minutes, such as India (UTC +5:30) and Nepal (UTC +5:45).


The duality of the A&S1309 and A&S8513 manufacture calibres also influenced the design of the movements, taking the form of complete symmetry along the 12 and 6 o’clock axis. The dials of each time zone therefore face each other both on the DTE and the DBG Skeleton. The two tourbillons of the DTE adopt this same principle. This symmetry reflects both mechanical order and a particular vision of the world.

Indeed, in a GMT watch, there is a hierarchy between the two time zones. The local time dominates, while the original time serves as more of a reminder. Due to its influence on the history of marine chronometers, Arnold & Son places the two times on an equal footing. The two are inseparable, as their difference is what indicates a ship’s position on the sea. This functional and historical vocation takes on a contemporary form in these two timepieces to reflect a past that is still alive to this day.

Globetrotter Night

Night flight

At once graphic, cartographic and hemispherical, the Globetrotter Night gives its display of world times over to the night. Beneath a crystal dome, this timepiece plays on nocturnal nuances and city lights.

In the 1780s, John Arnold contributed to the great revolution in ocean navigation with his marine chronometers. The Globetrotter Night reflects this historical legacy with its cartographic features and world times. As night follows day, Arnold & Son cloaks its Globetrotter in darkness, spectacularly showcasing our northern hemisphere when shrouded in vesperal shadow.

Panoramic vision

Beneath a large sapphire crystal dome, an arch supports a half-globe in shades of grey and blue. It depicts the continents, the seas and the lights of the large cities located north of the equator. On the edge of the planet, a sapphire ring breaks down the 24 hours of a day. Transparent between 6 am and 6 pm, a metal treatment has been used to darken it, indicating the night-time hours. Together, the hemisphere and ring display the time in one part of the world, represented in a highly original way. In the absence of a dedicated hand or city disc, the time is read geographically in accordance with the continents.

The Earth by night

The Globetrotter Night offers a realistic and meticulously rendered interpretation of a three-dimensional map enclosed in a 45 mm steel case. Chemical engraving has been used on the half-globe to outline the continents. The raised parts have undergone a deep-grey galvanic treatment before being hand-lacquered in a black-grey hue, while the oceans are lacquered in grey-blue. Finally, the city lights twinkling in the northern hemisphere are represented by hand-applied silver sparkles.

The decorative touches and finishes adorning the Globetrotter Night extend beyond the Earth itself. The chapter ring is circular satin-brushed and the hands, despite being mostly concealed beneath the half-globe, are polished and accentuated by red lacquered tips. The large double-foot bridge supporting the half-globe is a spectacular feature in itself that lends structure to the overall appearance of this timepiece. It is circular satin-brushed and chamfered by hand and held in place by screws with polished heads and chamfered slots.

Watchmaking ergonomics

These finishes are echoed extensively on the A&S6022 self-winding calibre powering the Globetrotter Night. Entirely developed and produced by the Arnold & Son Manufacture, it has a nocturnal style thanks to the widespread use of NAC-type surface treatments. The bridges are polished and chamfered, finished with Côtes de Genève stripes and coloured grey. The skeletonised oscillating weight is engraved and treated chemically with ADLC black and NAC grey to obtain a two-tone appearance using a matt straight-grained finish.

Beyond these aesthetic details, what makes the A&S6022 calibre special is its easy setting, thanks to a three-position crown. The first winds the movement. The second adjusts the local time hand by one-hour jumps either clockwise or anti-clockwise. The third regulates the hours and minutes in addition to the planet’s rotation. When travelling to a different time zone, the second position enables the wearer to change local time while keeping world time synchronised.

In the interests of fairness, Arnold & Son can also provide a “southern hemisphere” version of its Globetrotter Night on request at the same price.

Deftly blending its British heritage with its Swiss watchmaking savoir-faire, Arnold & Son offers a new calibre to its Time Pyramid collection. With a skeletonized pyramid-shaped tourbillon seemingly floating between two sapphire crystals, the Time Pyramid Tourbillon is a true rendition of technical prowess and sleek elegance.

The Time Pyramid Tourbillon presents a cohesive combination of watchmaking feats organized in a pyramidal architecture. The skeletonised calibre A&S8615 pays tribute to the John Arnold’s regulators with their distinctive hours, minutes and seconds on different axes. The movement is built on three levels. The tourbillon and the two power reserve indicators are superposed by a sapphire crystal dial indicating the hours itself, crowned with a rhodium plated ring for the minutes. This exclusive construction offers a lively-look and three-dimensional face to the timepiece and, to further enhance the balance and symmetry, the crown is positioned at six o’clock.

The gear train runs vertically in a linear arrangement connecting the two barrels at six o’clock to the tourbillon escapement at twelve o’clock, giving the movement its pyramidal architecture. The bridges are designed so that all the wheels, the two mainspring barrels, the escapement and balance wheel are all visible from the dial side.

Besides the off-centred hours and minutes, seconds are on the tourbillon and the two power reserve indicators are on each side of the linear gear train. The blued steel hands indicating these power reserves artfully demonstrate how the right barrel takes over when the left barrel reaches a limited power and thus, to maintain an optimum and accurate functioning. The two serially set up barrels supply the in-house manufactured calibre with a total of 90-hour power reserve and provide a more regular force to the wheel train.

To meet with Arnold & Son finishing standards, the movement of the Time Pyramid Tourbillon is decorated with chamfered bridges, polished edges and Côtes de Genève while the main plate is satin-finished, the A&S three-spoke wheels chamfered, the edges polished, and the screws blued. The top bridge and cage plate of the tourbillon are circular satin-finished, chamfered and mirror-polished by hand.

The Time Pyramid Tourbillon is housed in a 44.6 mm diameter 18-karat red gold or stainless steel case and adorned with a hand-stitched alligator strap.

About the name

The Time Pyramid is inspired by the regulators created by John and Roger Arnold over two hundred years ago and by antique British skeleton clocks with their recognizable vertical construction and cone-shaped chain and fusee system.

The HM Perpetual Moon Aventurine offers a spectacular solid gold moon phase beautifully harmonising with a sparkling blue aventurine quartz dial and paired with an in-house Arnold & Son mechanical calibre.

Demonstrating its British history and Swiss savoir-faire, Arnold & Son presents the HM Perpetual Moon with a blue aventurine quartz dial, preserving the House’s expertise in astronomical complications.

The timepiece houses the exclusive Arnold & Son mechanical hand-wound calibre A&S1512 exclusively developed for the moon phases complication and equipped with a double barrel to yield a 90-hour power reserve. This movement supply a precision moon phase with one day deviation every 122 years and offers a unique easy-to-set feature thanks to the addition of a second moon phases indicator visible through the transparent case back.


Beyond technological aspects of the HM Perpetual Moon Aventurine, the entire rhodium plated movement features hand finishing including: chamfered with polished edges, Côtes de Genève and fine circular grained bridges, circular grained wheels, blued screws with polished and chamfered edges.
In addition, the moon phase guilloché disc, running from 10 o’clock to 2 o’clock, reveals a solid 18-karat red gold engraved moon. Faceted hours and minutes hands run along twelve golden indexes applied on the blue aventurine quartz dial.

The 42 mm diameter, 18-karat red gold case is sealed with an antireflection sapphire crystal and adorned with a hand-stitched alligator strap, fastened with an 18-karat red gold pin buckle.

HM Perpetual Moon Aventurine – Technical specifications

Functions Hours, minutes, precision moon phase indicator, second moon phase indicator case back
Calibre A&S1512, mechanical hand-wound
Jewels 27
Diameter 34 mm
Height 5.35 mm
Power reserve 90 hours
Frequency 3 Hz / 21,600 vph
Decoration Rhodium plated Haute Horlogerie finishing: hand chamfered bridges with polished edges, circular graining and sunray Côtes de Genève, blued screws with polished and chamfered edges
Dial Blue aventurine quartz, blue lacquered guilloché moon disc, solid 18-karat red gold (5N) moon and golden stars
Back: fine circular graining, rhodium plated, moon phase indicator
Material 18-karat red gold (5N)
Diameter 42 mm
Thickness 11.43 mm
Crystal Cambered sapphire, antireflection coating on both sides
Back Sapphire crystal
Water resistance 30 m /100 ft
Strap Material Hand-stitched brown alligator leather
Buckle Pin, 18-karat red gold (5N)
Reference number 1GLAR.A01A.C123A
Limited edition 28 pieces
World retail price CHF 31’900 (prices can be subject to change)

The three-dimensional, openwork movement and dial of the Nebula offer views into the very heart of the in-house manufacture calibre. Its gold case has been reinvented in a 38 mm diameter, magnifying the hypnotic micro-mechanical spectacle of the hand-wound movement.

Besides the careful attention to equilibrium, the powerful allure of the Nebula also derives from the calculated proportions and ratios of diameter versus height, size and placement of every gear and wheel. Rather than being an assembly of disparate components – case, dial, and movement – Nebula was designed from the ground up to be completely holistic, with all components blending harmoniously into one. For instance, no less than ten bridges of this complex calibre form the dial.

Highly legible hours and minutes rotate above the movement conceived and developed from the outset to be open rather than have superfluous material skeletonized as an afterthought. The revised sloping chapter ring and faceted golden indexes complete the impactful visual effect of the Nebula 38mm.

The balanced construction of A&S 5101 calibre – horizontally and vertically symmetrical, both front and back – explains the watch lovers’ strong attraction to the refined Nebula 38mm. On the dial side, symmetry at top to bottom is provided by the two mainspring barrels, which provide a very healthy 90 hours of power above, and small seconds plus the oscillating balance wheel below. Seven of the skeletonized and chamfered triangular bridges with polished edges fixed around the perimeter of the movement and radiating inward, offer a contemporary take on traditional architecture.

Not only is all of the movement visible and highly decorated – barrels, gear train, balance and escapement, and winding mechanism – can be appreciated from the dial side. But that’s not to say the underside of the movement is something to be overlooked.

The view through the display back reveals even more finishing, with skeletonized and chamfered main plate with polished edges, solid 18-karat gold settings and gears featuring polished chamfers. The Nebula 38mm is available in a red gold case, in a limited edition of 50.

About the name
“Nebula” (Latin for “cloud”) refers to the astronomical term describing a giant cloud of dust and gas thrown out by the explosion of a dying star. Nebulae are also regions where new stars are beginning to form. The seven bridges on the dial side radiate from the centre toward the perimeter and give an impression of stellar explosion to the sculptural movement.

Nebula 38mm – Technical specifications

Functions Hours, minutes, small seconds
Calibre A&S5101, hand-wound,
Jewels 24
Diameter 31.50 mm
Height 4.04 mm
Power reserve 90 hours
Frequency 3 Hz / 21,600 vph
Decoration Skeletonized movement, palladium-treated bridges, NAC-treated main plate, chamfered bridges with polished edges and brushed surfaces, chamfered wheels with A&S three-spoke design and polished edges, gold settings, bevelled screws with mirror-polished heads
Dial Rhodium plated chapter ring
Material 18-karat red gold (5N)
Diameter 38.00 mm
Thickness 8.91 mm
Crystal Cambered sapphire, anti-reflection coating on both sides
Back Sapphire crystal
Water resistance 30 m /100 ft

Material Hand-stitched brandy or grey alligator leather
Buckle Pin, 18-karat red gold (5N)

Reference number 1NEBR.A01A.C144A (brandy leather) / 1NEBR.A01A.C147A (grey leather)

Limited edition 50

World retail price CHF 23’300 without taxes (prices can be subject to change)