Astrolabe: Shipwreck find 'earliest navigation tool'

http://www.bbc.com/news/science-environment-41724022

by Thevet • 9 years ago

48 16 9 years ago

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.)

rimliu• 9 years ago

Just get her a copy of this: https://www.amazon.com/Longitude-Genius-Greatest-Scientific-... :)

yoodenvranx2• 9 years ago

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

moftz• 9 years ago

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.

yoodenvranx2• 9 years ago

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.

zazen• 9 years ago

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.

johnlbevan2• 9 years ago

It's not a great headline given many navigational tools vastly predate this. E.g. the (arguably) most obvious maritime navigational tool being the compass:

https://en.wikipedia.org/wiki/History_of_the_compass#Early_n...

The compass was used in Song Dynasty China by the military for navigational orienteering by 1040–44,[15][28][29] and was used for maritime navigation by 1111 to 1117

abrowne2• 9 years ago

The whole article has some issues: https://thonyc.wordpress.com/2017/10/24/getting-names-right-...

LeifCarrotson2• 9 years ago

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]"

gshubert17• 9 years ago

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

http://www.chirurgeon.org/files/Chaucer.pdf

MaysonL• 9 years ago

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

jcrei• 9 years ago

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.

LeifCarrotson2• 9 years ago

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.

roywiggins• 9 years ago

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.

sosborn• 9 years ago

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

The sea is a cruel mistress. Ships regularly get wiped out despite state-of-the-art navigation. I would suspect that the vast majority of shipwrecks throughout mankind's history has little do with navigation and everything to do with the inherent danger of the open ocean.

Astrolabe: Shipwreck find 'earliest navigation tool'

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