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"Second" chances

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Re: "Second" chances
Post by Louis R   » Sat Jun 11, 2022 4:13 pm

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There is indeed explicit mention of celestial navigation being taught to midshipmen - and the contempt which the traditionalists felt for such effete methods when dead reckoning and [the equivalent of] rutters had served perfectly well since the Creation.

Salisria wrote:
Louis R wrote:Good, relatively inexpensive chronometry, perhaps. _accurate_ chronometry was the domain of the mariner - it doesn't matter to a train if your watch is off by a few seconds, but the rock ripping out your keel wouldn't have been there if you weren't those few seconds off in your longitude calculation.

We don't have any mention of ships' chronometers in the series. I don't recall any mention of using sun or star sightings to establish positions until airships are available, and those more stable platforms won't require anything as complicated for accurate timekeeping.

As for trains, if one is running trains on a single track line, accurate timekeeping is definitely needed to avoid head on collisions unless one is going to inefficiently limit when trains go each way to specific times of day.

Historically, railroads achieved time synchronization using electrically synchronized clocks. I doubt semaphore synchronized clocks could be more than a minute or two in synchrony, though that might be sufficient for railroad use, if traffic loads aren't that high.
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Re: "Second" chances
Post by Salisria   » Sat Jun 11, 2022 10:56 pm

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Now that you mention it, I do recall that scene, but IIRC the emphasis was on how the new Arabic numerals (and possibly trigonometric tables and/or slide rules as well) now made it practical rather than any improvements in chronography.
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Re: "Second" chances
Post by Keith_w   » Sun Jun 12, 2022 3:52 pm

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Salisria wrote:Now that you mention it, I do recall that scene, but IIRC the emphasis was on how the new Arabic numerals (and possibly trigonometric tables and/or slide rules as well) now made it practical rather than any improvements in chronography.


I believe that should be Horology.

Horology ("the study of time", related to Latin horologium from Greek ὡρολόγιον, "instrument for telling the hour", from ὥρα hṓra "hour; time" and -o- interfix and suffix -logy)[1][2] is the study of the measurement of time. Clocks, watches, clockwork, sundials, hourglasses, clepsydras, timers, time recorders, marine chronometers, and atomic clocks are all examples of instruments used to measure time. In current usage, horology refers mainly to the study of mechanical time-keeping devices, while chronometry more broadly includes electronic devices that have largely supplanted mechanical clocks for the best accuracy and precision in time-keeping.

https://en.wikipedia.org/wiki/Horology
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A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.
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Re: "Second" chances
Post by isaac_newton   » Fri Jun 17, 2022 9:47 am

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Salisria wrote:SNIP

As for trains, if one is running trains on a single track line, accurate timekeeping is definitely needed to avoid head on collisions unless one is going to inefficiently limit when trains go each way to specific times of day.



I'm not a train expert, but IIRC some single lines ran using a physical 'key', so the driver could only proceed if he received the key for the next stretch from a signal man. He would then hand the key over at the next 'switch point' to another single man [or next driver if another train was waiting there].

that would seem to be a bit more efeicient than limiting to specific time periods. I suspect I have overlooked some subtleties :-)
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