astrolabe

3 Articles

Maritime Analog Computer From 1503 Is The Oldest Remaining

March 20, 2019 by 19 Comments

We might not think of analog computers as having existed in the 1500s, but in fact the astrolabe first appeared around 220 BC. However, as you might expect only a few very old ones still exist. Early astrolabes were often wooden and were difficult to use aboard ships, however brass astrolabes with special features were more accurate on the deck of a ship underway. A recent archeological find from one of Vasco da Gama’s ships that sunk in the Arabian Sea has brought the number of known archeologically-significant instruments to 104, and also is one of the few nautical versions to employ a solid disk. As of now, it is the oldest known maritime astrolabe found so far — the ship sunk in 1503. You might wonder how the 104th astrolabe became number 108, but the catalog includes a few pieces or fragments of astrolabes. If you count those, there are 108 items in the catalog.

If you think archeology is about men in fedoras carrying whips, or stuffy old men wandering around tombs, you should have a look at the article about this find. In addition to divers recovering the piece from the shipwreck (see the video, below), the science involved in restoring it and analyzing it includes chemistry, lasers, X-rays, and energy-dispersive spectroscopy.

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Simple Hand Tools Turn Brass And Steel Into An Amazing Astrolabe

February 9, 2019 by 12 Comments

There’s something enchanting about ancient tools and instruments. The idea that our forebears were able to fashion precision mechanisms with nothing but the simplest hand tools is fascinating. And watching someone recreate the feat, such as by building an astrolabe by hand, can be very appealing too.

The astrolabe is an ancient astronomical tool of incredible versatility, allowing the user to do everything from calculating when the sun will rise to predicting the positions of dozens of stars in the night sky. That it accomplishes all this with only a few moving parts makes it all the more fascinating. [Uri Tuchman] began the astrolabe build shown in the video below with only a few hand tools. He quickly had his fill of the manual fretsaw work, though, and whipped up a simple scroll saw powered by an old sewing machine foot treadle to speed up his work. The real treat though is the hand engraving, a skill that [Uri] has clearly mastered. We couldn’t help musing that a CNC router could do the same thing so much more quickly, but watching [Uri] do it was so much more satisfying. Everything about the build really makes a statement, from the contrasting brass and steel parts to the choice of complex Arabic script for the markings. [Uri] has another video that goes over astrolabe basics and his design process that’s well worth watching too.

While it’s nowhere near as complicated an instrument, this astrolabe puts us in the mood to watch the entire Clickspring clock build again. And [Chris] is working on his own ancient instrument build at the moment, recreating the Antikythera mechanism. We can’t wait to binge-watch that one too.

Continue reading “Simple Hand Tools Turn Brass And Steel Into An Amazing Astrolabe” →

13th Century Navigation System

November 28, 2009 by 27 Comments

[ted id=694]

[Tom Wujec] explains how an astrolabe works and its importance in our technological development. He argues that an astrolabe was the world’s first “popular computer”. It measures the sky and that measurement can be used to tell time, survey land, and navigate a ship.

Astrolabes are built from three pieces and according to [Tom], educated children in the 1200’s would not just have been able to use one, but could build one as well. Electronics have certainly made our lives easier, but there’s something powerful about such a useful yet simple device.