The Excalibur Bi-Retrograde Calendar by Roger Dubuis

This year, Roger Dubuis celebrates its 30th anniversary, and for the occasion, the company pays tribute to its co-founder’s favourite complication: the bi-retrograde display.

This function, previously featured in the Excalibur Grande Complication alongside a dozen other highly complex mechanisms, takes centre stage once again. The Maison has also introduced a less complicated, more classic edition to further honour the bi-retrograde display.

Also referred to as “the ecliptic counters” by the Maison a nod to their elliptical shape and distinctive role in indicating the months and date the design showcases a symmetrical dial layout. Enhanced by refined detailing, it pays homage to the Maison’s early creations from 1996.

Glossary

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Glossary
Sidereal day

Sidereal day

Sidereal day is the time it takes for the Earth to complete one rotation with respect to the stars (using a fixed point) instead of the Sun, which is approximately 23 hours, 56 minutes, and 4.0916 seconds.

Some specialized clocks or timepieces have been designed to display sidereal time, which is based on the Earth's rotation relative to distant celestial bodies. These clocks often feature an additional sub-dial or display screen indicating the current sidereal time, allowing professionals in fields such as astronomy and navigation to track astronomical events with precision.