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Safehold clocks

This fascinating series is a combination of historical seafaring, swashbuckling adventure, and high technological science-fiction. Join us in a discussion!
Safehold clocks
Post by JBNL1972   » Thu Jul 06, 2017 3:07 pm

JBNL1972
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First of all hi, new person here on the forums, been stalking/reading for a while now, loving the Safehold series and eagerly awaiting the continuation!!

Anyway, clocks!
(I know i nthe grand scheme of things this is a really small thing, but I feel so proud for having had a lucid moment, I felt like sharing!)

I had a bright moment the other day in a lost hour where my mind wandered, and wondered how a mechanical/analog society would implement a 26 hour, 31 minute clock that reliably repeated and kept time.

And then it hit me: A Safehold clock would have 2 dials.
A main dial, divided into 13 hours, and a secondary dial divided into 31 minutes (Langhorne's Watch)

The clock mechanic would be set up to repeat the main dial twice, then switch to the seocndary dial, and repeat afterwards.
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Re: Safehold clocks
Post by WeberFan   » Thu Jul 06, 2017 5:50 pm

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I think you're overcomplicating things...

Any mechanical timepiece can be adjusted to keep pretty much whatever time you want. Of course, if it's designed to keep 24-hour time, then it will keep 24-hour time plus or minus a bit, but if you design it for a non-24-hour standard, then it'll keep to whatever it's designed for.

For example...

I have an old (80 year old perhaps) completely mechanical grandfather clock that keeps remarkably good time. But when spring and fall roll around, I have to adjust the length of the pendulum to account for shrinkage or expansion in the wooden pendulum. If I wanted to, I could adjust the pendulum length to keep to a 24.5-hour day... Of course this would look weird on a 12-hour clock face - twice around plus 15 minutes each cycle. That's just adjusting the speed of the pendulum.

But I've dismantled the clock a number of times over the past 30 years for periodic cleaning and noticed that everything is gear-driven inside. By simply adjusting the diameters of the various gears, I have no doubt that I could make the "small hand" describe one full circle not in 12 hours but in 26 hours. Ergo... only one clock face required, and a simple mechanic construction. I've got no doubt that this kind of clock is in use on Safehold, even if I don't recall any specific textev for it... And if you can make a "grandfather clock" do this kind of thing, then a watchmaker could do the same with a smaller timepiece. I recall a scene on Destiny where Prince Davyn and the Hanth kids were in a trig class and were learning how to figure out their latitude and longitude from solar and stellar observations. To do THAT, you need a pretty precise time standard (you've got to know when local noon is when you take your sextant observation for example).
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Re: Safehold clocks
Post by Hildum   » Thu Jul 06, 2017 8:13 pm

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Actually, there have been far more complicated clocks used on Earth. Western culture concepts of time come from Babylonians, who used several different number bases for counting and other purposes, but this concept of time was not universal.

The Japanese divided the day and night into six periods each, with the day running from dawn till dusk. This means that the length of an "hour" changes continuously during the year, and the length of the day "hours" and night "hours" are different. Mechanically, clocks were built with two pendulums - one for day and the other for night. The clock automatically switched between the two every morning and evening.

The pendulums were horizontal bars swinging back and forth on a vertical axis, with the period controlled by weights hung from the bars. Each bar had twenty-six slots for the weights, and they were moved manually every two weeks to account for the changing length of the hours.
Last edited by Hildum on Mon Jul 24, 2017 2:22 pm, edited 1 time in total.
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Re: Safehold clocks
Post by Keith_w   » Fri Jul 07, 2017 7:13 am

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Location: Ontario, Canada

WeberFan wrote:I think you're overcomplicating things...

Any mechanical timepiece can be adjusted to keep pretty much whatever time you want. Of course, if it's designed to keep 24-hour time, then it will keep 24-hour time plus or minus a bit, but if you design it for a non-24-hour standard, then it'll keep to whatever it's designed for.

For example...

I have an old (80 year old perhaps) completely mechanical grandfather clock that keeps remarkably good time. But when spring and fall roll around, I have to adjust the length of the pendulum to account for shrinkage or expansion in the wooden pendulum. If I wanted to, I could adjust the pendulum length to keep to a 24.5-hour day... Of course this would look weird on a 12-hour clock face - twice around plus 15 minutes each cycle. That's just adjusting the speed of the pendulum.

But I've dismantled the clock a number of times over the past 30 years for periodic cleaning and noticed that everything is gear-driven inside. By simply adjusting the diameters of the various gears, I have no doubt that I could make the "small hand" describe one full circle not in 12 hours but in 26 hours. Ergo... only one clock face required, and a simple mechanic construction. I've got no doubt that this kind of clock is in use on Safehold, even if I don't recall any specific textev for it... And if you can make a "grandfather clock" do this kind of thing, then a watchmaker could do the same with a smaller timepiece. I recall a scene on Destiny where Prince Davyn and the Hanth kids were in a trig class and were learning how to figure out their latitude and longitude from solar and stellar observations. To do THAT, you need a pretty precise time standard (you've got to know when local noon is when you take your sextant observation for example).


Thanks for the discussion of your clock. However, I do believe that you need to know what time it is at your 0 point (on Earth, Greenwich, England), not when it is local noon, when you take your sight which is why accurate clocks were required to determine latitude (angle between the horizon and either the sun or Polaris) or longitude (angle between the moon and another celestial object.

Intro to the Wikipedia on the Sextant:
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as sighting or shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart -- for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) to estimate latitude. Sighting the height of a landmark can give a measure of distance off and, held horizontally, a sextant can measure angles between objects for a position on a chart.[1] A sextant can also be used to measure the lunar distance between the moon and another celestial object (such as a star or planet) in order to determine Greenwich Mean Time and hence longitude. The principle of the instrument was first implemented around 1730 by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but it was also found later in the unpublished writings of Isaac Newton (1643–1727). In 1922, it was modified for aeronautical navigation by Portuguese navigator and Naval Officer Gago Coutinho.

https://en.wikipedia.org/wiki/Sextant
--
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: Safehold clocks
Post by Robert_A_Woodward   » Sat Jul 08, 2017 12:08 am

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WeberFan wrote:I think you're overcomplicating things...

Any mechanical timepiece can be adjusted to keep pretty much whatever time you want. Of course, if it's designed to keep 24-hour time, then it will keep 24-hour time plus or minus a bit, but if you design it for a non-24-hour standard, then it'll keep to whatever it's designed for.

(SNIP)


The problem is that extra 31 minutes stuck into the middle of the succession of hours of 60 minutes each. Basically, every clock has to mark time (i.e., the hands don't move) for 31 minutes every day before continuing.
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Beowulf was bad.
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Re: Safehold clocks
Post by JBNL1972   » Sat Jul 08, 2017 2:10 am

JBNL1972
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Robert_A_Woodward wrote:The problem is that extra 31 minutes stuck into the middle of the succession of hours of 60 minutes each. Basically, every clock has to mark time (i.e., the hands don't move) for 31 minutes every day before continuing.


This is how I got my "second dial" brainwave, because of those 31 minutes.

Also, since those 31 minutes are religiously significant (I recall reading you're supposed to spend them in contemplation) it'd even make sense in the world context for them to be extra visible/specially marked!
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Re: Safehold clocks
Post by WeberFan   » Sat Jul 08, 2017 12:04 pm

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JBNL1972 wrote:
Robert_A_Woodward wrote:The problem is that extra 31 minutes stuck into the middle of the succession of hours of 60 minutes each. Basically, every clock has to mark time (i.e., the hands don't move) for 31 minutes every day before continuing.


This is how I got my "second dial" brainwave, because of those 31 minutes.

Also, since those 31 minutes are religiously significant (I recall reading you're supposed to spend them in contemplation) it'd even make sense in the world context for them to be extra visible/specially marked!

I guess I don't see the logic of it... I mean, I completely understand that the time it takes Safehold to rotate is 26 Safehold hours plus another 31 safehold minutes that always occur at the same time every night. Simple enough.

If I understand the clock, there are a certain number of hours, with each hour consisting of a number of minutes. Langhorne's Watch is 31 minutes, but each of those minutes is the same duration of any other minute in the day. So in my head, I picture a clock face that has 26 equal divisions, plus another than is roughly half the size of any of the 26 other divisions. The extra half-hour or so would always take place at the same time (following one circuit of the rest of the clock face).
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Re: Safehold clocks
Post by JBNL1972   » Sat Jul 08, 2017 12:31 pm

JBNL1972
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WeberFan wrote:
JBNL1972 wrote:I guess I don't see the logic of it... I mean, I completely understand that the time it takes Safehold to rotate is 26 Safehold hours plus another 31 safehold minutes that always occur at the same time every night. Simple enough.

If I understand the clock, there are a certain number of hours, with each hour consisting of a number of minutes. Langhorne's Watch is 31 minutes, but each of those minutes is the same duration of any other minute in the day. So in my head, I picture a clock face that has 26 equal divisions, plus another than is roughly half the size of any of the 26 other divisions. The extra half-hour or so would always take place at the same time (following one circuit of the rest of the clock face).


But as far as I understand, a Safehold hour is still 60 minutes.

So every 26 hours, you'd have to run the clock for 31 minutes .... and reset it to the next full hour.

So I'd imagine it'd be easier for the clockmaker to add that second dial/mechanic with a mechanical switch to run his "main" clock for 13 hours full circle twice, then stop it for the secondary clock running a full circle of 31 minutes, then resume the main clock again and repeating.

Essentially:
Main Clock runs 00:01 to 13:00 (AM) (full rotation/hours/minutes)
Main clock runs 13:01 to 26:00 (PM)(full rotation/hours/minutes)
Secondary clock runs 00:00 to 00:31 (Langhorne's Watch)
Clock repeats
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Re: Safehold clocks
Post by zyffyr   » Sat Jul 08, 2017 3:07 pm

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JBNL1972 wrote:Essentially:
Main Clock runs 00:01 to 13:00 (AM) (full rotation/hours/minutes)
Main clock runs 13:01 to 26:00 (PM)(full rotation/hours/minutes)
Secondary clock runs 00:00 to 00:31 (Langhorne's Watch)
Clock repeats



I think it would be simpler to do :

Main Clock runs for 26 hours.
Secondary clock runs for 31 minutes.
Repeat.

The only reason clocks still have 12 hours on them instead of 24 is cultural inertial - we have always made them that way so we still do.

Since the 'Angels' were creating an entirely new culture, they have room to be reasonable and simplify to once around for the main day. After all, the more complicated the mechanism needed to make those clocks the more likely it is that someone might actually learn something from looking at it, and that would be "A Bad Thing(tm)".
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Re: Safehold clocks
Post by dobriennm   » Sat Jul 08, 2017 4:15 pm

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Of course, this complexity is all due to Langhorne's mistake in setting up the original calendar and time divisions (see note below of why I think this happened)

There is a much better way of setting up the calendar and clock by simply re-defining the "Safehold" second.

Year - 301 days (10 months + 1 day to match Safehold's rotation about the sun)
Month - 30 days
day - 30 hours
hour - 60 minutes
minutes - 60 "Safehold" seconds
"Safehold" second - 0.88389 "Earth" seconds (to 5 decimal places)

(there are 95,460 "Earth" seconds in a Safehold day, 108,000 "Safehold" seconds in a Safehold Day as I defined it)

A "second", after all, is something we humans define, so we could define it any way we want to.

This would also be something else the Archangels could have proclaimed as miraculous - all these nice even divisions of time.
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Note - Reasons this probably wouldn't happen (from the point of view of the characters in the story).
1. Cultural inertia - the command crew was use to doing comp time to keep the standard definition of a second.
2. Laziness
3. Shan Wei and her team were first on the planet and would have seen no reason to change the definition of a second. From their stand point, it would have made the Alexandria Library harder to use because of all the needed conversions. Plus, why bother when you're going to go out and colonize other planets in the future which will need comp time anyway.
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