What does 1.55 millimeters look like? It doesn't look like much at all.In fact, a US regulation quarter is 1.75mm thick.Now consider this: the Audemars Corum 101.251.90/E040PN34 Watch Piguet Jules Audemars Extra-Thin watch features a self-winding movement that is only 2.45mm thick, less than two quarters stacked on top of each other.The entire watch is only 6.7mm thick.Then, consider AP's Jules Audemars Perpetual Calendar, a watch with a movement that consists of 355 separate components and doesn't require setting until March 1st, 2100.
He came up with this system as a way replica Breitling A4935011-G5-361A Men's watch for pilots to quickly and accurately determine their Greenwich Hour Angle, otherwise known as longitude.We have featured a few of the Longines Lindberghs in the past but both were pretty run of the mill.Today's, however, is not.It is a rare and original Longines Hour Angle watch with a face that shows the logo of a 200+ year old sea-going group of guys originally formed by Alexander Hamilton.We're talking about The Revenue Cutter Service, of course.
So if you are adding the functionality of a perpetual Corum 101.251.90/E040PN44 Watch calendar to a 2.45mm thick movement (that's 141 additional components, btw) how much do you think that would add? Probably a lot, right? Typically you'd be right, but here, the base 2120 caliber becomes a perpetual calendar with only the addition of 1.55mm in depth, less than one quarter's thickness.So, the entire perpetual calendar movement is only 4mm thick, just over the height of two quarters stacked on top of each other.Think about that, say to yourself "no way," and then come to your senses and realize Hodinkee would never lie to you.
