ChronoAcademy0/10 lessons

Complications · Lesson 8 of 10

The Chronograph

A stopwatch built into your watch: pushers, totalizers, and how to read them.

A chronograph is a stopwatch built into a watch — the complication that timed motor races, fighter sorties, and, on Apollo 13, a 14-second engine burn that helped bring three astronauts home. It's also the complication most likely to confuse a new owner, because its biggest hand doesn't do what you think.

A working chronographTop pusher: start/stop. Bottom pusher: reset (when stopped).
30-MINSECONDS

00:00.00

The big violet hand is the chronograph seconds — it only moves when you're timing. The little dial at 6 o'clock is the watch's normal running seconds, ticking away regardless. The counter at 12 totals your elapsed minutes.

Reading the dial

  • Central chrono hand — the stopwatch seconds. Parked at 12 until you start timing. One lap = one minute.
  • Minute totalizer — a subdial (usually 30 minutes) counting how many laps the chrono hand has made.
  • Running seconds — a small subdial showing the watch's own seconds, always ticking. Proof the watch is alive even when the chronograph sleeps.

Pusher etiquette

Top pusher (2 o'clock): start, stop, restart. Bottom pusher (4 o'clock): reset — and on traditional mechanical chronographs, only after stopping. Slamming reset mid-run can hurt older movements (modern ones usually just ignore it). And unless the manual says otherwise, don't work the pushers underwater.

Words you'll meet

A tachymeter is the scale on many chronograph bezels: time one mile or kilometre, and the chrono hand points at your average speed. A flyback resets and restarts with a single press; a rattrapante (split-seconds) has two stacked hands for timing two things at once. All ways of asking a wrist-sized machine to do more.

Knowledge check

3 quick questions to lock in what you just learned.