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Can the _Book of Hastings_ be Broken?

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Can the _Book of Hastings_ be Broken?
Post by Robert_A_Woodward   » Sat Jan 02, 2021 1:37 am

Robert_A_Woodward
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I had earlier posted "Breaking the Book of Hastings", but I have been thinking over the problem and now wonder whether it could be possible.

The basic thrust is that the Book of Hastings used a Ptolemaic system to describe the heavens. But when Merlin considered it to be Ptolemaic, was it strict Ptolemaic (with a non-rotating Safehold) or was it just a Safehold-centric system? The first would be falsified by a Foucault pendulum, the second would not be. There were many geo-centric models back in the day, some with the Earth rotating, and one even having Venus and Mercury circling the Sun. I did notice that there is no evidence that there is anything in the Safehold system other than the sun, Safehold, and its moon, Langhorne. Presumably, there is also at least one asteroid belt (because the presence of such was part of the original mission plan and the terraforming crew weren't told that Langhorne was going to change the plan).

I brought up parallax, but dismissed it, because the very concept was heretical. But, then I remembered proper motion, which is not only about the same magnitude of parallax for nearby stars, but also accumulates, year by year, decade by decade, century by century. But, I also realized that Langhorne's crew had a fix for that. While not yet mentioned in the series, Safehold (whose axis inclination is greater than Earth's) will experience precession. It will probably be less than Earth's because Earth's is mostly driven by the Moon which is significantly larger than Safehold's moon, Langhorn. However, apparent stellar motion for that reason would be noticeable enough for the Order of Hastings to periodically (say once a century) issue an update for stellar locations in longitude and latitude. Since the mystic device (i.e., computer system) that produces that update should have the proper motion of all visible stars, each update would be correct. Theoretically, if somebody compared the locations of certain stars over several updates, they would determine that there were extra displacements.

However, who, other than the Royal College of Charis, would have kept those old books? Old books which were destroyed by arson in _By Schism Rent Asunder_.
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Beowulf was bad.
(first sentence of Chapter VI of _Space Viking_ by H. Beam Piper)
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Re: Can the _Book of Hastings_ be Broken?
Post by Keith_w   » Mon Jan 11, 2021 6:58 am

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Robert_A_Woodward wrote: However, apparent stellar motion for that reason would be noticeable enough for the Order of Hastings to periodically (say once a century) issue an update for stellar locations in longitude and latitude. Since the mystic device (i.e., computer system) that produces that update should have the proper motion of all visible stars, each update would be correct. Theoretically, if somebody compared the locations of certain stars over several updates, they would determine that there were extra displacements.
<snipped for brevity>

No need to offer updates to the Book of Hastings. Safeholdians did not use longitude and latitude to get places until Merlin introduced sextants, they used their rutters.
--
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: Can the _Book of Hastings_ be Broken?
Post by Louis R   » Mon Jan 11, 2021 9:26 pm

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I expect that Robert used longitude and latitude refer to what astronomers usually call declination and right ascension. Things that only matter to people who have to make rather precise measurements of the positions of the sun and planets. In real history, this was done for the purposes of astrology, _not_ navigation. And unless Langhorne and Co. were even more complete idiots than they seem to have been astrology would have no part in Safeholdian culture. Which means that it's unlikely that anyone would be looking closely enough at the sky to even notice precession. Since it doesn't affect the relative positions of the stars in the sky, even the relatively large amount that occurs on earth in a human lifetime isn't apparent to the casual observer. Unless Safehold has a planet/satellite mass ratio comparable to our system's, the amount of precession that will occur in a single life will be far smaller - too small to ever be an issue.

And, whatever the original explanation may have been, I would lay odds on the current version of the Writ ascribing any anomalies that might be noticed to the imperfections of the world induced by Shan Wei's rebellion.

Keith_w wrote:
Robert_A_Woodward wrote: However, apparent stellar motion for that reason would be noticeable enough for the Order of Hastings to periodically (say once a century) issue an update for stellar locations in longitude and latitude. Since the mystic device (i.e., computer system) that produces that update should have the proper motion of all visible stars, each update would be correct. Theoretically, if somebody compared the locations of certain stars over several updates, they would determine that there were extra displacements.
<snipped for brevity>

No need to offer updates to the Book of Hastings. Safeholdians did not use longitude and latitude to get places until Merlin introduced sextants, they used their rutters.
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Re: Can the _Book of Hastings_ be Broken?
Post by Robert_A_Woodward   » Fri Jan 15, 2021 1:34 am

Robert_A_Woodward
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Keith_w wrote:
Robert_A_Woodward wrote: However, apparent stellar motion for that reason would be noticeable enough for the Order of Hastings to periodically (say once a century) issue an update for stellar locations in longitude and latitude. Since the mystic device (i.e., computer system) that produces that update should have the proper motion of all visible stars, each update would be correct. Theoretically, if somebody compared the locations of certain stars over several updates, they would determine that there were extra displacements.
<snipped for brevity>

No need to offer updates to the Book of Hastings. Safeholdians did not use longitude and latitude to get places until Merlin introduced sextants, they used their rutters.


But the possibility of using the stars was always present. Which means somebody would try to use them. I will point out (not that Langhorne and company would know it) that the Polynesians associated stars with islands in their navigation scheme - no sextants were used. And, if they were used, the fact that the unchanging stellar sphere wasn't unchanging would become noticeable after sufficient time has passed.
----------------------------
Beowulf was bad.
(first sentence of Chapter VI of _Space Viking_ by H. Beam Piper)
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