wtf is a chronograph?

[angelabaca]

So I bought my friend a watch as a congratulatory gift for completing his marathon this past weekend.

The watch comes with a chronograph. What the hell does that do?

[viking]

That would be fancy market-speak for a stopwatch.

[angelabaca]

are you serious? A stop watch? I fiddled with that think for half an hour and I couldn’t figure out what it did!

thanks

[astro]

What is the difference between a Chronometer and a Chronograph?

[sub]These two similar terms are both used with watches and are easily confused.

The simple answer is that a chronometer is a certified accurate timepiece, a chronograph is a timepiece with stopwatch functions. So for any watch, one, both, or neither terms may apply.

Chronograph
Any watch with stopwatch functions can be called a chronograph. This has nothing to do with any measurement of accuracy, it is merely a statement that the watch has this function.

In watch industry terms, the elapsed time measurement functions of a chronograph are some of the many ‘complications’ beyond the basic timekeeping functions of a watch mechanism. Even watches with quartz movements may implement these complications through mechanical gears, wheels, and dials. Other watch complications include date indicators, alarms, moon phase displays, multiple time zone features, and other time-related measurements shown with additional hands, windows, or sub-dials on the watch.

Chronometer
The first need for very accurate timepieces came from ships needing precision timekeeping to allow precise celestial navigation. The term chronometer came in to use to describe timepieces accurate enough for ship navigation. In 1973, the Controle Officiel Suisse des Chronometeres (COSC) came in to existence as the official testing and certification control board.

Now, only a watch whose movement has been certified by COSC can be called a chronometer. For a typical men’s-sized mechanical watch movement, it must have stayed within -4 to +6 seconds of variation per day during the COSC measurement at various temperatures and positions.

COSC also certifies quartz movements (their standard is +/-0.2 second per day for these). But since quartz movements are inherently very accurate and suffer little to no variation based on position or normal temperature ranges, certification is much less significant to buyers of quartz movement watches. Almost no watchmakers go to the expense to have COSC certify their quartz movements.

A chronometer certificate is not a guarantee of future accuracy. Watch movements that have been certified can get out of adjustment and perform poorly. Movements that were not certified may still exceed the COSC standards–the manufacturer may simply have simply chosen to bypass the expense of the certification process.

[/sub]

[Trigonal_Planar]

Isn’t a chronograph a device for accurately measuring the speeds of projectiles (specifically, bullets). They have two “panels” parallel to each through which the projectile passes. I don’t know how they work exactly*, but from this it calculates the speed.

(*aside from the obvious fact that they find the entrance time, exit time and they know the distance between those points)

[Trigonal_Planar]

Isn’t a chronograph a device for accurately measuring the speeds of projectiles (specifically, bullets). They have two “panels” parallel to each through which the projectile passes. I don’t know how they work exactly*, but from this it calculates the speed.

(*aside from the obvious fact that they find the entrance time, exit time and they know the distance between those points)

[viking]

Well, yes, in some circumstances it is (and I believe they work by having an optical sensor that detects the shadow of the passing bullet; the ones I’ve seen have a white 1" strip mounted above the eye' against which to see’ it). But somehow I have trouble seeing one of those as a feature on a watch, so I assume it graphs' (displays) the chronos’ (time) between pressing a start and stop button instead