t the meeting point of astronomy and Genevan watchmaking excellence, Roger Dubuis unveils a new timepiece defined by celestial rhythm. This calming and elegant creation not only counts the unfolding units of time on Earth, but it also tracks the precise phases of the Moon, all expressed through the Maison’s distinctive aesthetics and a new upgraded calibre.

As with all Roger Dubuis creations at Watches and Wonders Geneva 2026, the Maison has drawn inspiration from the movements of the sky, and the stellar observations that have shaped humanity’s understanding of time and space. Through precise calendars and horological displays, these new novelties do not merely indicate the hours, they also pay tribute to the motion and beauty found beyond our planet, awakening the imagination, and embodying the precision and mysteries within the universe.

Mastering the perpetual calendar is one of watchmaking’s most demanding pursuits – and one that captivated Mr. Roger Dubuis. His patient nature and quiet perseverance was ideally suited to the complication’s complexity, which requires dedicated time and a passionate approach. It has therefore remained a signature complication, and one that has showcased the Maison’s commitment and technical devotion throughout the decades.

This latest perpetual calendar is arranged with a signature biretrograde display, in which the day and date indications sweep across elliptic scales before returning to their starting point at the completion of each cycle.

Ever since Mr. Roger Dubuis co-patented his own biretrograde display with Jean- Marc Wiederrecht in 1989 and showcased it in the very first watches of the Maison in 1996, the style has brought a special sense of flair to the dials.

One of the “big four” complications in watchmaking, the perpetual calendar is engineered to precisely track the passage of time by accounting for the varying lengths of months and even the rhythm of leap years. More than a display of hours and days, it reveals the very architecture of time itself. A version that is properly set today would continue to present the correct date flawlessly until the year 2100.

Inside the watch, the new RD850 Calibre represents an upgraded generation of Roger Dubuis’ biretrograde perpetual calendar movements.

Delivering 60 hours of power reserve, and comprised of 435 components, this self- winding calibre has been developed and crafted entirely in-house at Roger Dubuis’ Geneva manufacture.

A key functional improvement compared to previous versions of perpetual calendar movements is the addition of a month corrector, which allows the month indication to be manually set with one simple adjustment. This new upgrade makes regulation much faster and easier, while also preventing over-use of the function.

Adding to the intricacy of the RD850, an astronomical Moonphase has been integrated at 6 o’clock. This display is engineered to follow the Moon’s orbital cycle around the Earth, rounded to 29 days, 12 hours, and 45 minutes - the time it takes to move from one new Moon to the next.

In practical terms, this means the display shows the waxing and waning of the Moon almost exactly as it appears in the sky. While a standard Moonphase mechanism typically rounds the cycle of the moon to an approximate 29.5 days, creating a deviation of one day every two to three years, this Roger Dubuis astronomical Moonphase will remain accurate for around 122 years, before requiring its first adjustment with just one click.

Importantly, the RD850 has earned Poinçon de Genève, a third-party certification of Genevan watchmaking excellence, and a hallmark of Roger Dubuis’ own high- quality standards. This prestigious seal attests not only to the movement’s origin in the Canton of Geneva, but also to the character of its construction, finishing, and performance.

In particular, the 19 different finishes across this calibre display a comprehensive level of skill and masterful technique.

One of the rarest and most distinctive of these is the inner angle finishing. A traditional mark of high horology, this challenging technique is achieved by the craftspeople who, using their specialised tools, work to press and push the material, resulting in the final polished look. The inner angle finishing can now be admired specifically on the w-shaped bridges of the retrograde mechanisms at 3 and 9 o’clock, appearing 14 times.

Like peering into the night sky, the watch’s open-work dial reveals nine unique layers and a new “Astral Blue” colourway - a shade that evokes the profound vastness of the universe, and the infinite tones that can be observed in the deepest galaxies.

The layers include:

• A double-surface flange with a broad azuré finish.
• Ecliptic counters, made in Astral Blue mother-of-pearl with polished angles.
• An Astral Blue month disc in mother-of-pearl.
• A leap year disc at 1 o’clock, with circular brushing and a grey colour coating.
• The circular-brushed main plate dial with a grey colour coating.
• A Moonphase counter, distinguished by Astral Blue mother-of-pearl.
• A main Moonphase disc, crafted in aventurine with a domed 18K pink gold moon that is laser-engraved to add richness and texture.
• The open-work calibre with its inner angled finishing on the retrograde bridges.
• A main plate module, notable for its sun-brushing and grey colour coating.

At an elegant 40 mm size, the timepiece comes in 18K pink gold. Completing the design, the Excalibur Biretrograde Perpetual Calendar is presented on an Astral Blue calfskin leather strap.