Glashütte Original’s new perpetual calendar builds, quite literally, on the German brand’s biggest development in recent years, the impressive Calibre 36. The automatic base calibre boasts not only 100 hours power reserve on a single 68cm mainspring and a bayonet-fitting movement mount but also undergoes a 24-day barrage of tests that would certainly seem to be far more intensive than the independent COSC procedure. Owners of Calibre 36-based watches are then presented with individual certificates listing the most obvious of these test results, while an online portal offers a deeper look its performance and the tests themselves.
Glashütte Original had enough faith in the performance of this new movement to create the range-topping Senator Excellence collection especially for it. This collection already includes a three-hander, grand date and grand date moon phase alongside the new Calibre 36-02 based perpetual calendar.
The perpetual calendar presents day, grand date, month and moon phase along with a slightly superfluous leap year indicator that would have been, were the Calibre 36-02 an integrated perpetual calendar, better reserved for the caseback side. The grand date is simply one of the best on the market, consisting of two concentric discs on the same plane with very quick, if not instant, clickover.
Where the dial is one of the watch’s great strengths, the reverse side is perhaps its most underwhelming aspect, all the sapphire caseback reveals is the winding rotor (featuring the brand's oddly dated back-to-back G motif), its four-wheel winding train and the escapement. Being fairly flat it’s not the most ambitious canvas on which to showcase the brand’s excellent decorative capabilities.
By stacking the perpetual calendar mechanism on top of the base calibre, the Senator Excellence Perpetual Calendar is a third taller than the time-only version at 12.8mm which, by no means a deal-breaker, does make for a substantial watch. It also means that the crown sits low on the caseband, closer to the reverse than the dial side, with the perpetual calendar’s quick-set correctors sitting higher.
But living with the Senator Excellence Perpetual Calendar you begin to understand the faith Glashütte Original has placed in its new movement, You quickly develop a confidence in this watch with its reassuring 'set down/pick up' power reserve, certified accuracy and the anti-magnetic properties of its silicon balance.
There’s also the price, which thanks to this new modular strategy of GO comes in at a very reasonable £15,400. It might not be the most affordable mechanical perpetual calendar on the market - Frederique Constant - currently holds that title - but given the meticulous development of calibre and the well-considered presentation of information on the dial, it does feel like something of a bargain.