Chronometers and watches

[ewsponberg]

Originally Posted by Paul L

You might want to record ambient temperature during the period, as that will have a large effect on the error. That is why wearing a digital watch ( ei5th or without a digital didplay) can help keep it accurate, as the temperature changes little due to body heat.

Well, I can't really do anything about the ambient temperature, it is what it is, and being in the tropics for the next 6-8 months is going to keep temperatures pretty even.

The advice was to use 3 watches to compare them together for accuracy, rather than wear them. I already wear a digital/analog watch (has both readouts) so I don't need nor want to wear 4 watches. If the watches seem to wander, I'll know to suspect temperature variation, and if they do wander, I am hoping that they'll wander at a consistent rate and in the same direction, either consistently slow or fast. The last watch we had was terribly inconsistent, sometimes it would go fast, and sometimes it would go slow, on a daily basis. That's what started this whole test.

Again, thanks for everyone's input.

Eric

[Paul L]

Originally Posted by ewsponberg

Well, I can't really do anything about the ambient temperature, it is what it is, and being in the tropics for the next 6-8 months is going to keep temperatures pretty even.

The advice was to use 3 watches to compare them together for accuracy, rather than wear them. I already wear a digital/analog watch (has both readouts) so I don't need nor want to wear 4 watches. If the watches seem to wander, I'll know to suspect temperature variation, and if they do wander, I am hoping that they'll wander at a consistent rate and in the same direction, either consistently slow or fast. The last watch we had was terribly inconsistent, sometimes it would go fast, and sometimes it would go slow, on a daily basis. That's what started this whole test.

Again, thanks for everyone's input.

Eric

Just pointing out that temperature is a very big issue in accuracy. If you test a watch at constant temperature you will not know how it performs when it is then cold when you get off the South African coast. A false sense of security is only marginally useful.

[StuM]

Originally Posted by ewsponberg

So, relying on good ol' Amazon, I was able to find inexpensive Casio analog watches for OZ$24.41 each, about US$17.00. The watch model number is MQ-24-7BLL, a men's watch with white dial, no date window, and a black plastic strap.

Why did you want an analog display?
What's wrong with digital?

[Jammer]

Hi Eric


Thanks for the updates.


Time and synchronicity are subjects of professional interest to me as well as being a sort of hobby.


I have had a HAQ (high accuracy quartz) watch for over a year. It is advertised as being accurate to within 10 seconds a year. I find that its accuracy is somewhat less but still very good, around +/- 20 seconds a year in practice if it is worn constantly. If it is not worn and is left in an unusually hot or cold area it will gain or loose time. It is a Certina DS Action Precidrive. While it was a gift I understand that they cost around US$ 500. There are several models. Mine is suitable for scuba diving and I use it for that also.


It does have a date window but it can be reset without changing the time.


I have a high-precision time source at work that is accurate to within less than 1 mS and I check it against that occasionally.

[Singularity]

Originally Posted by StuM

Why did you want an analog display?
What's wrong with digital?

FWIW, and perhaps you're familiar, but the debate over the conceptualization of time being linear vs cyclical goes way back, gets religious, and technical. Clearly at least a few percent of people literally see +/- feel time as cyclical (space-time synesthesia) while English at least contains metaphor coming from the cyclical camp (e.g. "those who don't study history are 'bound' to repeat it"...as though such people are tethered by gravity to remain in the same orbital path, or on an elliptical like a moth to a flame).

Point being at least that analog is simply more natural to some people than others, even if they don't know why.

I bet at least 2% of people have this synesthesia and may have never even paid attention to it (no less knew that it was unusual perception in the first place). No doubt some people on this board have it and may prefer an analog display.

[El Pinguino]

Captain Lecky in his 'Wrinkles' devotes a full 41 pages to chronometers... he was of the opinion that at least three should be carried... this being pre radio time signals.

Pic below from 'Wrinkles' shows how they were rated when at sea...

Back in old fashioned times I used to have either a Seiko or a Citizen watch... same concept as this... https://watchdirect.com.au/citizen-a...ens-watch.html
You could/can toggle between digital time and date.. quite handy when a long way from the Greenwich meridian. I kept the hands on local time and the digital on GMT both time and date.

[El Pinguino]

Originally Posted by Adelie

0.5nm.

in longitude... if you are on the equator..... 0.4 nm in the Bay of Islands...

[El Pinguino]

Originally Posted by StuM

Why did you want an analog display?
What's wrong with digital?

Don't need to put my glasses on to read analog............

[ewsponberg]

Originally Posted by StuM

Why did you want an analog display?
What's wrong with digital?

I simply prefer looking at a dial rather than digits when I am the one keeping time and my wife is shooting the sextant. There is nothing wrong with either, just personal preference.

[slug]

Originally Posted by ewsponberg

On Corroboree we have a sextant as back-up to our electronic navigation (iNavX software on two iPads). To use it, of course, you need an accurate timepiece. In the past we have used wrist watches, but these days they don't keep very good time. I would like to know from the Forum what would you recommend for a good watch or timepiece to track time, independent of what we have on our electronic devices? Is there a brand or type of watch (either wrist watch or pocket watch) that you like? How much did you pay for it? I would like a small analog watch with a second hand, and preferably one without the little day/date window (as they always need resetting and often break). We have a bulkhead-mounted clock, but that is not easy to use when we are in the cockpit taking sights, plus it is not all that accurate.

As a matter of interest, we left Florida in January 2017 and we are now in Bundaberg, Australia, so we have managed to get nearly halfway around the world. We'll be here for the next 6-9 months or so before continuing our voyage. We practice sun sights with our sextant when at sea, and we would like to use a timepiece rather than the iPad clocks just to make sure we are totally independent of electronics in our sight reductions.

I welcome any and all advice.

Eric

I record the time of observation with a stop watch

My chronometer is an inexpensive Casio compact digital desk clock.. time and date .. bold numbers , battery powered and it also has an alarm function so you don’t forget your longitude at noon pair observation


It stays down below and is interrogated with the stop watch

Handy to have a shipmate down below if you are doing a round of observations

I don’t like wrist watches and tiny displays

[tkeithlu]

EW, you may not realize that you are circuling history. Remember Darwin's Beagle? It's "real" job was charting the South American coast for the Royal Navy; Darwin was just along for the ride. Charting requires accurate determination of longitude. The Beagle carried 21 chronometers, with the result averaged. Error at the end of the voyage was interpolated, as in 1/2 of this error should be applied 1/2 of the way through the trip.

I'm a beginner on celestial, but have found that knowing the rate of error for the Timex on my wrist allows me to keep the error within a second between checks against WWV or GPS.

Don't forget that a GPS unit knows the exact time because it could not work without. Even WWV has auditory and speed of light from the source errors, but too small for you to apply to a sight.