Monochrome Watches
An online magazine dedicated to fine watches

The New Jacob & Co. Astronomia Regulateur

Jacob’s spin on a watchmaking classic…

| By Xavier Markl | 3 min read |

Jacob & Co. is renowned for crafting some of the wildest, craziest and most complicated watches. The design can be polarizing, but one undeniable fact remains: these watches are truly spectacular. The debut of the inaugural Astronomia in 2014 caused quite a stir at Baselworld. Staging a poetic portrayal of the celestial world, its concept relies on planetary displays in perpetual motion, all under the control of a multiple-axis tourbillon. This distinctive design has sparked a saga of numerous iterations, each showcasing a variety of technical enhancements and background sceneries. Using this concept, Jacob and Co. releases a spectacular take on a watchmaking classic: the “regulator”, floating in a 3D stage and crafted in rose gold and blue…

Historically, watch workshops and observatories were equipped with precision master clocks known as regulators. Designed for precision time reading, these mother clocks featured a distinct display format, prioritizing separate time indications, typically spotlighting the minutes hand at the centre. The term “regulator” relates today to dials showcasing distinct time registers, typically featuring a central minutes hand accompanied by subsidiary registers for hours and seconds.

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The Astronomia Regulateur is the latest in Jacob’s “carrousel movement” series. Its rotating movement carries three arms. One is for the one-minute flying tourbillon, while the other two arms are dedicated to the time display, one for the minutes and one for the hours, both made of a blue, translucent material. As these sub-dials rotate with the platform, they would be unreadable most of the time. To counteract this, differential mechanisms rotate the dials in the opposite direction, ensuring they always remain upright. The all-important seconds indication of this unique regulator can be read thanks to a golden hand emerging from the base of the movement on a blue translucent ring rotating counter-clockwise in 60 seconds.

Indeed, the all-new construction has a rotation speed of 60 seconds for the platform. The Astronomia started at one rotation every 20 minutes, then pushed the speed to one rotation every 10 minutes, one every 5 minutes and, for the first time, once every minute with the 2023 Astronomia Revolution. One of the main technical challenges with this rapid rotation is power management.

To support the remarkable power required for its rotation, the movement must store a significant amount of energy. But handling such a powerful force is easier said than done. The force supplied by the barrel(s) in a watch tends to be irregular. Initially, it delivers strong torque when fully wound, gradually diminishing over the duration of the power reserve. This variance impacts the timekeeping accuracy because balance wheels are not perfectly isochronous.

Consequently, Jacob & Co. developed a constant force mechanism to equalize the force exerted by the mainsprings. It consists of an intermediate spring reloading six times per second. Constant force is initially used to even out the energy received by the balance wheel to make it more accurate. This is crucial in achieving a consistent rate and sustaining a smooth, uniform rotation for the movement’s platform every minute.

Powering the Jacob & Co. Astronomia Regulateur, the calibre JCAM56 is the slimmest Astronomia-type movement to date. It allowed the creation of an Astronomia with wrist-friendly proportions (relatively speaking) with a diameter of 43 mm and a thickness of 18 mm. A veritable technical feat, the case is fashioned out of rose gold with openworked lugs and two large sapphire panes (the domed crystal and the case band), providing captivating views of the intricate movement from different perspectives.

The Jacob & Co. Astronomia Regulateur is worn on an alligator strap and secured to the wrist by a rose gold folding buckle. A limited edition of 250 pieces, it retails for USD 280,000. For more information, please visit

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