The A. Lange & Söhne Perpetual Calendar Terraluna is big (45.5mm) and busy for a Lange timepiece, but retains the brand’s signature classic aesthetic. As a high complication, it conveys a lot of information but does so smoothly and elegantly. Hours are shown regulator-style in the subdial at four o’clock, with overlapping minute and seconds dials. There is also a leap year indicator, a rare and expensive complication, in the upper right. The caseback is a dramatic orbital moonphase display with not only moonphase but the moon’s position in the night sky from the northern hemisphere – so the watch also functions nicely as a nice day/night indicator. The balance wheel serves as the sun, and three moving disks represent the sky, earth and moon.
The movement, Caliber L096.1, is driven by two barrels and a constant force mechanism that ensures efficiency and regulates the torque. The result is unvarying amplitude and a high rate of accuracy. Other Lange signatures include a hand-engraved balance cock and lavishly hand decorated movement.