Triple Threat: This Omega Chronoscope Is Three Chronographs In One

The word “chronograph” is derived from Greek (like all truly great words) and means, more or less, “time writer” which was a perfectly fine name for some of the earliest chronographs – they were what’s called inking chronographs and they worked by putting a drop of ink on the dial of a watch, to mark elapsed time. The march of progress is however relentless, and the inking chrono has been consigned to the dustbin of history (although the way things are going these days, it would not surprise me in the least if someone ginned one up just for grins). The name however has stuck, although Omega has used the word Chronoscope on several occasions (a better word in general for modern chronographs) in the De Ville family, most recently in 2007, and in 2021, the name was used for the watch we have today for A Watch A Week: The Omega Speedmaster Chronoscope.

The Chronoscope has a Speedmaster Professional-style case, crown, bezel, and pushers and is equipped with a hand-wound, co-axial caliber 9908, which was a new-ish movement for the Chronoscope when it launched, being a manual version of the automatic caliber 9900. The watch is Master Chronometer certified as well, and size-wise, it’s only very slightly larger than a Moonwatch, at 43mm x 12.8mm. This particular panda-dial version was one of three dial variations introduced at launch; the other two were white with white subdials, and blue with white subdials. The watches all featured the tachymeter bezel common to all Speedies, and the Chronoscope throws in a telemeter scale and a pulsometer scale.

Some folks find these triple scale watches to be a little on the busy side, but there’s a lot of historical precedent for including all three – you can find all three scales combined on any number of vintage as well as some modern chronographs, and they’re a great way of adding additional functionality to the basic chronograph complication.

The Tachymeter: Measuring Speed

The tachymeter (from the Greek, “tachos” for speed and “metron” meaning, “to measure”) is the best known of the three and probably the most common in use in chronographs today across the board – the most touted use for it is to measure average speed over a measured distance. You start the chronograph as you pass the first distance marker and stop it when you pass the second, and whatever number the chronograph seconds hand stops at, is your speed in miles per hour. The tachymeter more generally is a units per hour measurement device, and you can use it to, for instance, determine the number of widgets per hour that are being made on an assembly line. If you start the chrono at the beginning of the manufacturing process, and stop it when one widget is completed, the seconds hand will point to the number of widgets per hour your production line can make (so for instance, if it turns out it takes a minute to make one widget, your production rate is sixty per hour).

If you happen to be counting fewer than sixty units/miles per hour, by the way, the two innermost of the inner scales on the dial are for measuring slower speeds. The outer of those two scales (both in red, in this model) will show you units per hour from 59 to 30, and the inner one, units per hour from 29 to 20.

The Telemeter: Measuring Distance

The outermost of the inner scales on the dial is a telemeter and once again, the name’s Greek: tele, “distance,” and “metron” to measure; thus, that which measures distance. The telemeter is used to measure the distance between you, the observer, and a distant event that produces both sound and light – the usual use case cited is a lightning flash. When you see the lightning, start the chronograph, and when the sound of thunder reaches you, stop the chrono and you can read off how far away the lightning fell (in kilometers, in this case). The event doesn’t have to be lightning, of course; you can use it to measure, say, the distance from the explosion of an artillery shell (something that would have been useful for zeroing in artillery barrages in the days before aerial spotting or radio equipped forward observers). The only potential gotcha is that the speed of sound in air does vary with things like air temperature, barometric pressure, and altitude, but for a person in most normal circumstances (ie it’s not sixty below zero, you’re not at 25,00 feet) the telemeter will give you a reasonable approximation.

The Pulsometer: Measuring Heart Rate

Finally we have the pulsometer, the etymology of which is obvious from preceding examples (although, interestingly enough, “pulse” is derived from Latin, not Greek, so the word is a mashup of Greek and Latin, which would make a philological purist’s hair stand on end, I suppose). The pulsometer allows you to measure beats per minute of the heart, via the pulse; you feel the pulse at the radial artery on the wrist (you can feel it elsewhere but the radial artery is the easiest); start the chrono and start counting pulse beats. If you are wondering how many beats you should count before stopping the chronograph, the dial says, helpfully, GRADUE POUR 30 PULSATIONS – calibrated for thirty pulsations, so stop when you have counted thirty, and wherever the seconds hand stops, is the number of beats per minute for your patient’s heart. The idea is to reduce the amount of time it takes to measure beats per minute, which would of course, always take a minute without the chronograph.

The scale lets you measure the heart rate from as slow as 30 BPM all the way up to a clinical red flag 200 BPM. The precision of your measurement depends on the heart rate being relatively stable and of course, modern laser pulsometers in rings and smartwatches make the pulsometer scale the one that is least likely to be used on a regular basis – although having said that, I can’t remember the last time I drove a measured kilometer or needed to know how far away a lightning strike was, either.

The Movement: Omega Co-Axial Caliber 9908

The movement runs at 4Hz in 44 jewels, with a very respectable 60 hour power reserve and is freesprung, with a silicon balance spring and co-axial escapement. As a Master Chronometer certified watch, the movement’s also resistant to magnetic fields as strong as 15,000 gauss if not more, and it runs within the Master Chronometer precision spec of ±2 seconds per day, or four second’s variation in daily rate total. Anecdotally, you can probably expect even better precision than this but you’re guaranteed the Master Chronometer spec at minimum.

The movement runs at 4Hz in 44 jewels, with a very respectable 60 hour power reserve and is freesprung, with a silicon balance spring and co-axial escapement. As a Master Chronometer certified watch, the movement’s also resistant to magnetic fields as strong as 15,000 gauss if not more, and it runs within the Master Chronometer precision spec of ±2 seconds per day, or four second’s variation in daily rate total. The movement is a 3/4 plate design with a balance bridge for the balance, making it very physically rigid (a good thing) and highly shock resistant.

Anecdotally, you can probably expect even better precision than this but you’re guaranteed the Master Chronometer spec at minimum. This is a column wheel controlled, vertical clutch chronograph movement, and while it has design nods to watchmaking history, like the “arabesque” Geneva stripes (Omega’s term) it is a technically advanced, thoroughly modern piece of micromechanical engineering.

If you like the idea of a feature rich, high precision wrist instrument with design nods to both the history of the Speedmaster case, as well as the legacy in watchmaking of mult-scale chronographs, this one’s for you. And it’s a great conversation piece as well. Plus, you never know when you’ll need to zero in a barrage from your field artillery; the charge across No Man’s Land that you save may be your own.

For pricing and availability, view the Omega Chronoscope in our pre-owned Omega collection. A Watch A Week is taking a couple of weeks off to smell the eggnog – we’ll see you all in 2026!