As you can see, the 48 hour power reserve is at 10/ 11 o'clock, the date and moonphase at 7 o'clock, and the small seconds at 4/ 5 o'clock on the porcelain dial, which features a railway track scale.
A beautiful polished Officer's style case (which Patek call the "Directoire" case) with a hinged cover over a sapphire crystal back opens up to show 265 parts, a 22k gold off-centre mini rotor, and the Patek Calibre 240 movement. The only thing that beats an open caseback, to me, anyway, is an Officer's case. Even if you aren't a movement nerd you'll find this beautiful and mesmerising.
First released by Patek Philippe in 1977, the Cal.240 was created as a thin base movement for PP's perpetual calendars. At only 2.4mm thick, with a Gyromax balance, the movement allows for a perpetual automatic caliber with a total thickness of only 3.7mm. As is evidenced by the Ref.5054, Cal.240 ended up being used for a variety of watches from the brand, not just perpetual calendars.
The watch is water-resistant to 25m, but I doubt that this has been tested out in the wild by any owner!
Unfortunately, the photos I took were less than ideal, but as the photo below shows, they were taken under less than ideal conditions. The appearance of the watch at one of our weekly GTGs was unexpected, so we had to make do with the rather old point & shoot cameras that we happened to have with us.