
Astrolabe: Shipwreck find 'earliest navigation tool' - Thevet
http://www.bbc.com/news/science-environment-41724022
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yoodenvranx
Slightly Offtopic:

If you are interested in how similar devices might have been made 100s and
1000s of years ago you should check out the latest videos on the Clickspring
Youtube Channel [1]. Chris is building a copy of the Antikythera mechanism
(mostly) without using modern tools and he is doing a stellar job.

The quality of his videos and his attention to detail is _amazing_! If you are
into this kind of stuff you will most likely end up binge watching his whole
channel over the weekend.

[1] [https://www.youtube.com/channel/UCworsKCR-
Sx6R6-BnIjS2MA](https://www.youtube.com/channel/UCworsKCR-Sx6R6-BnIjS2MA)

~~~
moftz
I see him using a mill and lathe multiple times. He even uses a CNC at least
once in part 5. All the machinery he uses would have been something available
to a machinist in the 50s. He's not using a plasma cutter but he's using
relatively modern tools that an ancient greek bronzesmith couldn't even dream
of.

~~~
yoodenvranx
That's why I wrote "... (mostly) ..." ;)

I think he just uses the Mill and the CNC to speed things up, but some parts
(like the gears) he does completeley by hand with a file even though he could
do it way faster and more precise on a mill.

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zazen
To clarify the headline: this is the earliest astrolabe _for maritime use_
_yet found_, dating to AD 1495-1502. Astrolabes in general go back to
classical times. I guess the headline is getting at that distinction with the
phrase "navigation tool", but it didn't become clear to me until I read TFA.

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abrowne
The whole article has some issues:
[https://thonyc.wordpress.com/2017/10/24/getting-names-
right-...](https://thonyc.wordpress.com/2017/10/24/getting-names-right-is-
rather-important-in-the-history-of-science/)

~~~
LeifCarrotson
Please don't just link to your blog instead of making a comment here.

At the very least, summarize your post and link to the extrapolation. _" This
is specifically a marine astrolabe for determining latitude from the elevation
of a specific star, not a generic astrolabe with many other functions. It's
also not the earliest navigational tool. These names and distinctions are
important, and getting them wrong is indicative of damaging, incorrect click-
bait journalism. I go into more detail on my blog: [link]"_

~~~
abrowne
Yes, I should have summarized, but it's not my blog, just one I read. So I was
just being lazy, posting as I went out through door to work, not trying to get
clicks on my site or something.

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LeifCarrotson
On a shipwreck, huh? That's an interesting place to find a new and effective
navigational tool. The boat carrying it should, in theory, be less likely to
become a shipwreck.

I wonder where else we can apply this observation?

In the use of ECC memory, maybe? Or when analyzing web analytics, perhaps: if
your site traffic only shows a small percentage of mobile users, you might
choose not to optimize for mobile browsers. But instead there could be a
problem with the source of your observation: Just like the archaeologists who
discovered this marine astrolabe aren't observing both successful and
unsuccessful sailors at that time in history, you're looking at the subset
which has shown up on and used your site, and who have analytics enabled. It
could be that mobile users aren't showing up in your "shipwrecks" because
they're quickly bouncing from your difficult-to-use site or because their
search engine can see that your site isn't optimized and it doesn't recommend
you to them.

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roywiggins
> The boat carrying it should, in theory, be less likely to become a
> shipwreck.

Alternatively, only a few boats would have had one, and the ones that did were
using them to strike out further afield than their less well-equipped
contemporaries. Since they could be more confident about their location, they
could venture further from land and might get caught by storms more easily.

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jcrei
The Portuguese first sailed and reached India in 1498 (Vasco da Gama). This
ship (nau in Portuguese) left Lisbon in 1502. It was part of the second voyage
of exploration from Portugal to India.

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gshubert17
Geoffrey Chaucer wrote perhaps the earliest technical manual about 1391, on
the astrolabe.

[http://www.chirurgeon.org/files/Chaucer.pdf](http://www.chirurgeon.org/files/Chaucer.pdf)

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MaysonL
Nasir al-Din al-Tusi (18 February 1201 – 26 June 1274) wrote one earlier. From
the Wikipedia article about him, a couple of his works:

al-Risalah al-Asturlabiyah – A Treatise on the astrolabe.

Zij-i Ilkhani (Ilkhanic Tables) – A major astronomical treatise, completed in
1272.

[https://en.wikipedia.org/wiki/Nasir_al-Din_al-
Tusi](https://en.wikipedia.org/wiki/Nasir_al-Din_al-Tusi)

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LiamMcCalloway
I spent last Sunday's lunch explaining to my girlfriend the revolution that
being able to compute your longitude was (I could not help myself). There were
prizes offered by the trading companies and governments to whomever would
devise a reliable way to determine one's longitude.

Conceptually, it's interesting that longitude is mostly useful only if you
know your latitude (that's because 1degre of change in longitude does not
translate to the same distance traveled whether you're at the equator or at
the pole.)

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rimliu
Just get her a copy of this: [https://www.amazon.com/Longitude-Genius-
Greatest-Scientific-...](https://www.amazon.com/Longitude-Genius-Greatest-
Scientific-Problem/dp/080271529X) :)

