F.P. Journe

I completely understand that he has been very busy with the Paris Boutique, but there are a lot of unanswered questions on the exact workings of the Centigraph, and judging from the amount of posts, significant interest in these answers.

Journe has positioned himself IMO amongst the finest watchmakers in the world, and has been able to attract a following, not only by inventing and making amazing timepieces, but by is almost academic approach to the discipline. This has largely been cultivated by his openness and transparency in his work, and people, I know I do, have become very suduced by this highly personal and perfectionist approach.

It would be wonderful if Mr journe, or someone from the firm, could continue this openness and enlighten us a little further on the centigraph's mechanism - There are some very clever people on these forums, and even they acknowledge there is still a lot we must not still understand about it.

It does seem to be a very intersting movement indeed and clearly why it must have won the recent Grand Prix de Geneve award, so I a not concerned that the "wool has been pulled over our eyes" as some posts were claiming at all. I looked at the panel of judges at the award ceremony, and they seem like a very informed and knowledgable group IMO. Therefore if they are happy with its claims, I certainly am but, am still very confused about some basic things.

Some simple questions are:

• Why does the flying second hand move in 1/16 sec intervals and not 1/6 sec intervals?
• Can it me as easily stopped within these intervals, or is there a higher probabiliy that it will be at 1/6th of a sec or 1/16th interval, if not why?
• How constant is the movement during one rotation of the scond hand?
• If a controled experiment were to be run, say by filming the watch running continuosly with a digital clock running in the background and the film were to be started and paused rapidly, would the time differences on the digital clock be the same or close to the dial readout.

I am really looking forward to whether some additional info can be released - it would rather re-complete by perfect opinion of the brand to date.

Thank you in advance

 

Mark

 

 

Dear Brad,

The escapement of the Centigraphe beats at 21600 and counts 6 stops per second. If there was nothing else to regulate the speed of the hand, it would look like the movement of a "foudroyante".

Thus, on the axis of the hand there is a 30 teeth wheel which works with a free lever.

This free lever slows down the speed of the axis of the hand 60 times per second; furthermore this axis is slowed down 6 times per second by the escapement of the watch.

The cinema taught us that to have a fluid image, 24 images are enough. There are 60 images/second in the vision of the movement of the hand, it is sufficient to see a fluid flow which we can stop at any moment.

Best regards,

FPJ

Nt

Cheers

Stephen

not 1/100th of a second. Why should it be called Centigraphe?????

And this answer does not confirm or disprove the Centigraphe's ability to be stopped at a particular 1/60th of a second, i.e., if one has a quick enough hand to start-stop the flying hand, there is still NO WAY we can stop it from the 3/60th second to the 15/60th second, say for example.

Would anyone thorw a better light to this answer???????????

 

Larry

No message body This message has been edited by markkeenan on 2008-12-17 01:25:16

still a bit confused as to why on the website it says the flying second hand moves in 1/16 sec increments, and don't if i am honest understand completely how the hand is slowed down by 1/60 sec but I am no watchmaker.

Essenatilly what is now clear to me is that the hand does 1 revolution / sec, which is well within the "spec" of the movement, and Mr Journe has developed three innovative things:

It has a separate power source so does not impact the amplitude of the watch when the chrono is activated and stopped.

The motion of the flying second hand has been smoothed from 6 jumps in one revolution to 60 (basically continuous motion based on the film analogy)

The ability to freeze the hand at any point.

 

Thus IMO I can sort of see that if you have a hand that does exactly one rotation / sec as smoothly as possible (2.5 times smoother than a movie clip) and it can be stopped at any point - increments down to 1/100th sec can be measured and the frequency is largely irrelevant.

Thank you Mr Journe

 

Mark

Brilliant explanation.
Thanks to Mark for his relentless pursue for an answer which in turns helped us better understand how the centigraphe works, and to Brad for providing us the information from the man himself.

On a side note, there is an interested interview of FP Journe in the latest popular watch magazine in which he spoke about the today's marketing gimmicks, abit on the latest minute repeater and his vision for the FP Journe in upcoming years. He also mentioned briefly in the interview about second coming Vagabondage which brad has told us earlier as well as Chronometre Optimum.... and a surprising quartz watch for women with 20 years of power reserve. Very interesting interview I must say.

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I'v didnt seem to catch brad's post about the 2nd iteration of the Vagabondage, care to show me the lead?

Also, what's this about a Chronometre Optimum, sounds like my kinda stuff!

I'm not in Singapore now, so can't get the magazine it might be in, so care to elaborate on what it said about the CO? At first thought it sounded like Optimus Prime! Haha maybe i'm thinking too much of Transformers lately because yesterday I just bought a new Transformer figure, Thundercracker from the Masterpiece collection!

So is it like a CS but adjusted for even more superb accuracy?

Cause that's what it sounds like to me!

Cheers

Stephen

Stephen,

In the interview, he simply mentioned Chronometre Optimum as one of the upcoming projects in the future. Nothing more I'm afraid.
I have came across 'Chronometre Optimum' in a previous interview. I am in the midst of browsing through my stack of magazines and so far, I am unsuccessful. If I recall correctly, he mentioned that the watch is of such accuracy that he decided to name it the Chronometre Optimum... somewhere in the lines of this but do not quote me on that. He also mentioned that the plans has been laid out but he simply do not have time to execute the task at  the present moment. (And yes, it sure does sound like Optimus Prime! lol.)

Perhaps, a PuristS interview could further clarify this??

Man it's pieces like this that "might" or rather "will" come out in the future that leads me to so want to save my money now for them!

This "Optimus Prime" of watches, i bet it lives up to its name! Because since I already own a CS, and it is truly THE MOST accurate watch in my entire collection, i can't imagine for an EVEN BETTER AND  MORE ACCURATE WATCH to come up!

But knowing Journe, i trust and believe in him, so here's a toast to the Optimus Prime coming!

Haha i'm talking too much abot Transformers now!

But hey, let this be the Optimus Prime of the Francois Paul Journe world, the Chronometre Optimum!

Cheers

Stephen

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An interesting article on Centrigraphe which I have just found.... Here are some of the excerpts (taken from Revolution Issue 11, by Ian Skellern)

Power for the chronograph function-

"Journe has used a similiar mainspring configuration to the one he invented for his Sonnerie Souveraine. The mainspring unwinds from both its inner and outer ends; the going train (timekeeping) is powered traditionally from the mainspring barrel; while the chronograph function takes its power from the (central) barrel arbor. This effectively isolates the operation of the chronograph from the timekeeping function, so that  there is virtually no drop in balance amplitude when the chronograph is activated."

Measuring intervals smaller than 1/16th of a second-

"When the chronograph is activated, the high-speed flying seconds hand does not spin smoothly like a figure skater, but jumps in micro-increments of 1/16th of a second, as expected for a balance oscillating at 21,600 vph.
The logical question then is: how can it possibly measure intervals of time smaller than 1/16th of a second?
Journe has achieved this by driving the flying seconds from both the going train of the movement working off the barrel and the chronograph train driven by the barrel arbor. When the chronograph is clicked to stop the measurement of elasped time, a pinion is vertically disengaged, disconnecting the escapement from the flying seconds, and simulaneously braking the hand.
This enables the flying seconds hand to stop any position along its dial - even between two 1/100th of a second divisions.

The mechanism is technically brilliant; however as I mentioned earlier, the 1/100th of a second precision may be more theoretical than real, as inconsistencies induced by the user's reaction time and the functioning of the micro-mechanics will certainly introduce practical limitations."

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This last one seems to suggest that, while the hand is running, it moves once every 1/16th of a second, but that when the user "stops" the hand, it can measure time in increments between two adjacent 1/16ths of a second.

Of course, it cannot literally be true that the watch moves the way it is described. The hand obviously cannot stop and start instantaneously. Rather, it has to slow down and speed up. Every 1/16th of a second, the hand must be stationary for some portion of that interval, and it must be moving for another portion of that interval (to a first approximation at least -- in fact, it may never be precisely stationary while ticking). So if you are going to allow the user to stop the hand between "ticks," the question of precision becomes, what is the stopped/moving duty cycle? If the stop button is pressed while the hand is moving, what happens? If it is pressed while the hand is "stopped", does the mechanism then advance it some fraction of the way towards the next 1/16th mark to true it up to whatever its actual temporal resolution is (1/60th of a second)?

And if it is the case that there is this shadow mechanism which can calibrate the position of the hand in finer increments than 1/16th of a second that only shows itself when the stop button is invoked, why not actually allow the hand to run in those increments rather than imposing this "high precision" mechanism only when the hand is stopped?

The analogy to film at 24 fps seems curious to me. Sure, movies are a series of still images that fool the eye into thinking that we are seeing motion. However, each image has an exposure time. The film camera has to advance to a new frame every 1/24th of a second. As a practical matter, the duty cycle is close to 50%, so 50% of each frame is taken up with moving from one frame to the next, suggesting that the longest exposure time per frame is roughly 1/50th of a second, or 20 milliseconds. Varying the exposure time within the limits set by the frame rate (that is, from 20 ms on down to, say, 0.5 ms) dramatically changes the appearance of what we see (shoot a water fountain at a longer exposure time and you see continuous flowing water, shoot it at a short exposure time and you start to see individual water droplets -- anyone familiar with a video camera that has a "normal" and "sports" mode will be familiar with this). But even if you do this, if you examine adjacent frames closely, you will see that fast moving objects will have advanced a finite distance between frames, not an infinitesimal one. The eye and brain interpolate between the two positions and make the motion look smoothe, but there is no actual information in the film about those intermediate positions that are never shown. Beyond that, 24 fps is merely an illusion that is "good enough" for movies etc. -- you can't measure fast events with this standard rate, and indeed, a visit to youtube will show you some interesting examples of very short events, like bullets being fired through apples or water balloons bursting, that need to be filmed at MUCH higher frame rates in order for the inherent detail to be seen. So even though 24 fps is good enough for government work, as they say, it is well known that higher frame rates reveal much greater temporal detail. So with this in mind, what is the difference between a watch that functions as the Centigraphe does and one that actually beats fast enough to stop the hand every 1/100th of a second? There must be some difference.

Also not discussed, but alluded to by others in this forum, is even if you have a mechanism that is theoretically capable of moving a hand in such increments, what limit on temporal resolution is imposed in actual practice by mechanical tolerances?

When the illusion of continuous motion presented by frame rates in film is referenced, it seems clear that the message is, "Don't think about it too hard."