A. Lange & Söhne Richard Lange Perpetual Calendar "Terraluna" ref. 180.026 Review

Richard Lange was Ferdinand Adolph's eldest son, and he was obsessed with precision. He was the one who spent years working on balance spring alloys and left behind a patent that watchmaking still uses today. The collection bearing his name follows suit, borrowing the regulator dials of scientific observation watches, where legibility takes precedence over everything else. This all makes the Terraluna the most surprising thing in that lineup, because the most instrument-minded line that A. Lange & Söhne builds ended up producing what is quite possibly its most romantic watch. 

This example is the ref. 180.026 in white gold, dated to 2021. The case clocks in at 45.5mm across and 16.5mm deep. There's no getting around it: this is a large watch, but for good reason! The argenté dial is solid silver and shows the hours, minutes, and seconds as three separate displays in a proper regulator fashion, with the outsize date above and the power reserve scale below. Day, month, and leap year sit alongside them, and the surprise is how orderly the whole thing remains, given how much it's displaying. 

The best part of the watch isn’t shown on the dial 

Flip the watch over, and the sapphire back shows Lange's patented orbital moon phase, which is a different proposition entirely from a moon disc peeking through an aperture. A blued celestial disc carries the moon around a gold earth while the balance wheel represents the sun, showing their relative positions as an observer in the northern hemisphere would actually see them. Lange quotes a deviation of one day across 1,058 years, which is impressive stuff. That said, that number matters less than the fact that the display is genuinely readable as astronomy rather than purely decoration. 

The hand-wound caliber L096.1 that drives it comprises 787 parts and 80 jewels, and features twin barrels that store 14 days of power. A constant-force escapement sits between those barrels and the balance, releasing an identical portion of energy every ten seconds, so the beat rate holds steady from day one to day fourteen. Very few watches even attempt that, and even fewer do so while running a perpetual calendar. 

The watch is in like-new condition, with its Lange box, a 2021 certificate, and service papers from A. Lange & Söhne dated 2023. It asks a lot of your wrist and gives back more than almost anything else at the price.