Tag: Astrolabe

Byzantine Astrolabe (sort of)

In a fragment attributed to John Kamateros on the astrolabe are a handful of interesting diagrams illustrating the various parts of an astrolabe. Here is the diagram showing the rete.

An illustration of an astrolabe’s rete, found in a 15th-century Byzantine fragment on the astrolabe.

There is also diagram illustrating the plate, and two showing different aspects of the back of the instrument.

Of Astrolabes and Wine

Further evidence that astrolabes are infiltrating culture is the name of winery in New Zealand: Astrolabe.

A winery in New Zealand has adopted the name “Astrolabe.”

Unfortunately, this winery is not really named after the instrument. Instead, situated in the Marlborough region of New Zealand, the winery is named “after the ship that in 1827 charted and explored the Marlborough Coast.” That ship was called “L’Astrolabe” (presumably after the instrument).

The L’Astrolabe was certainly the name of a ship, but an astrolabe isn’t now nor ever was a navigational instrument.

As much as I like the connection to the ship and the instrument, I regret that the owners have been mislead by a common myth about astrolabes being used as navigational instruments. Despite what we often hear and read, astrolabes were not navigational instruments. Yes, they could be used to determine elevation of celestial objects (as well as doing a whole host of calculations), but they were never used to navigate.[1]

Whatever the case, references to astrolabes are turning up more often in popular culture (even GoT jumped on the “astrolabe” bandwagon). Before long we are likely to see Astrolabe return the lists of popular baby names. Abelard and Héloïse were just a few centuries ahead of their time.


  1. Yes, the “Mariner’s astrolabe” was used to determine the elevation of celestial objects and thereby help to determine location. But that’s a different instrument. And while some people will argue that they are similar enough to allow for the slippage from one term to another, I am not such a person. Moreover, I would argue against the validity of claiming that one was subset of the other. And because this is my little sandbox, I get to be as pedantic and particular as I wish.  ↩

The Byzantine Astrolabe

I can’t reconstruct how I came across this page, but now that I have I can’t let it go without some comment. A search for the pair of terms “Brescia astrolabe” or “Byzantine astrolabe” gives as the second result a link to a Wikimedia page, Byzantine astrolabe at Brescia, 5th century AD (reconstruction).jpg

Some Wikimedia user thinks this astrolabe is a reconstruction of a 5th-century instrument. It’s not.

A quick point: this astrolabe is not a reconstruction of a “5th-century” astrolabe. The Byzantine astrolabe now in City Museum in Brescia is from the 11th century. It’s dated 1062, to be precise.

I wonder: the user who uploaded the image claims it was taken at The Technology Museum in Thessaloniki. Did the museum mislabel this display? Did the Wikimedia user misread/mislabel the file? I could not find a page for this astrolabe (I assume it is part of the Ancient Greek Technology) so I can’t determine if the museum is to blame here. The Wikimedia user claims to be a native Greek speaker, so misreading the label might surprise me. But who knows.

I assume the reconstruction is somewhere in this gallery at The Technology Museum in Thessaloniki.

In any case, if want to know more about the Brescia astrolabe you should download David King’s thoughts on this astrolabe, Byzantine Astrolabe of 1062. Or read O.M. Dalton’s old but still very reliable essay, The Byzantine Astrolabe at Brescia (1926). Regrettably, there are no high-resolution images of it on the internet, so you’ll just have to travel to Brescia to see it. In the mean time, here is (a copy) of the image from Dalton’s essay.

The front of the Byzantine astrolabe (from Dalton’s essay).

GoT Starbucks Cups and Astrolabes

Game of Thrones fans, and a disturbingly large part of the internet, erupted over an errant paper coffee cup, complete with plastic sippy lid that somehow found its way onto a table on set. For a few seconds during the feast celebrating the defeat of the Night King, on the table near Daenerys Stormborn of House Targaryen etc. etc. etc., sharp-eyed viewers caught a glimpse of the offending cup and immediately turned to the internet to express dismay and outrage. News outlets picked it up and ran with the story, trying among other things to determine if it was a Starbucks cup.[1]

Daenerys Stormborn of House Targaryen etc. etc. etc. and her cup of coffee.

To be fair, a paper to-go cup seems a bit casual for a banquet celebrating the survival of humans all over the seven kingdoms, as well as Essos and Sothoryos (I assume they too would have eventually fallen to the Night King). At least have one of those plastic, branded reusable cups. But whatever.

NY Times worried about that coffee cup.

Anyway, the uproar over the paper cup as some a violation of authenticity and veracity seems a bit misplaced in light of the willful disregard for both in every discussion of the opening sequence. We read again and again (and again and again) about the astrolabe in the opening sequence.

The GoT “astrolabe” as rendered in the opening sequence.

Even the creative director at one of the design firms that produced imagery for the opening sequence talks about the astrolabe. He shared the original concept for the instrument. Here it seems the sun is at the center with various bands rotating about it.

GoT “astrolabe” concept art.

The only problem? It’s not an astrolabe! It’s nothing like an astrolabe. It doesn’t project the heavens onto a plane. It doesn’t allow for the calculation of anything (let alone the altitude of a celestial body). It doesn’t track or map the motions of the stars. There are no zodiacal (fictional or otherwise) on it. It looks to be akin to an armillary sphere, except again it doesn’t display any celestial information. Looking at the concept art, it seems inspired by Eudoxus model for planetary motion, with its concentric, off-axis rotating rings.

A simple example of Eudoxus’ model for planetary motion, complete with off-axis, concentric spheres.

In any case, let’s be clear. Whether or not it was a Starbucks cup next to Daenerys in that banquet, it was at least a to-go cup (complete with sippy lid) that seems out of place. By contrast, that is certainly not an astrolabe in the opening sequence, however much it might seems like such an instrument belongs in Westeros.


  1. The pixels dedicated to the cup and explanations of the cup and interviews of people about the cup suggests either a really slow news day or the profound need for a little fantasy and escapism. Either would be a welcome change from reality.  ↩

Astrolabes and S•Town

On Thursday, February 16, at 5:36 PM I was standing in a faculty meeting when my phone vibrated. I fished it out of my pocket and looked at the screen. I had just received a voicemail and a text from the same number, a number I didn’t recognize. The text asked, simply: “Is this the phone of Darin Hayton?”

I stepped outside and listened to the voicemail. The person identified himself as a researcher for This American Life, asked if he had reached Darin Hayton, and wanted to ask about astrolabes. His message sounded urgent. I was intrigued. Why would anybody feel a pressing need to learn about astrolabes, at 5:30 on a Thursday evening? And why would that person not just turn to Wikipedia or some other on-line resource?[1] So I decided to respond.

As I was still, at least physically, in a meeting, I texted rather than phoned and offered to call later that evening or the next morning. He asked that I call him as soon as I was free.

Texting with the guy who turned out to be a researcher for This American Life.
When I phoned he immediately started asking about astrolabes. He had clearly done some research on them but wanted to confirm what he had learned—e.g., Hipparchus had developed the mathematics but not an instrument; early instruments dated from the late 9th century; you could use it to tell time. He was particularly interested in developments introduced by 10th-century Islamic scholars. He asked about different innovations we might attribute to them and wanted to know how they improved the astrolabe. Most of the innovations he mentioned cannot easily or definitively be traced back to early Islamic instrument makers. We chatted for 10–15 minutes. As our conversation wound down, I tried to find out why he was so interested in astrolabes. He offered few details, saying only that he was doing research for an up-coming This American Life show on a man from Alabama who had studied astrolabes and had even built his own. He wouldn’t tell me the man’s name, but did mention that he had recently died.[2]

After we hung up I tweeted about my brush with fame. I am clearly a nerd since I think having This American Life phone me constitutes fame.

I tweeted about my brush with fame—clearly I’m a nerd because I think talking to This American Life constitutes fame.
Fifteen minutes or so later as I stood in my bathroom brushing my teeth, my phone rang again. Same guy confirming a couple points and asking if his formulation was correct. Something to the effect: the Greek astronomer Hipparchus developed the mathematics behind the astrolabe and 10th-century Islamic scholars refined it to time their daily prayers. Yes, I said, that’s fine.

Because I am always late to the party, I didn’t hear about S•Town until late April, a month or so after it was released and became an instant hit.[3] Finally, when a friend suggested I listen to it because they “talk about astrolabes,” I downloaded it and listened while I repaired my washing machine. Sure enough, about 15 minutes in John B. McLemore (the main character) mentions astrolabes:

Because kids are talking about getting girls, or deer hunting, or football. Whereas I was interested in the astrolabe, sundials, projective geometry, new age music, climate change, and how to solve Rubik’s cube.


But he doesn’t say much more. Then, 30 minutes later, the astrolabe suddenly returns in the context of telling time.[4] Brian Reed, the host, reflects on various methods for tracking time, then describes the astrolabe:

BRIAN REED: The astrolabe looks kind of like a clock crossed with a compass. It’s a flat dial with a map of the night sky laid over it, and a pointer, or I guess a sight, attached on top of that. You pick a star in the sky, and aim the sight at it, twist the sky map until it aligns with the sight in a certain way. And then the dial shows you your direction, as well as the month, day, and time.

It’s a beautiful, complex device. And as a kid, John longed to figure it out, to put himself inside the brains of the people who puzzled through the earliest versions—the Greek astronomer Hipparchus, who devised the mathematics behind it, or the 10th century Islamic scholars, who refined the invention to help them time their daily prayers.

John wanted to go through what they had to go through to create an astrolabe. Which is why he made his own, designed specifically for the coordinates of this house. It hangs on the wall of his mother’s bedroom. That’s what he’s showing me, his astrolabe, when Skyler Goodson happens to walk in the front door.

When I heard this, I immediately recalled the man who had phoned six weeks earlier asking about astrolabes. There, in Brian Reed’s brief description, was the final version of what the man on the phone had crafted. It turns out that the man on the phone had been doing research for S•Town.

Thanks to S•Town and John B. McLemore, astrolabes are enjoying their 15 minutes of fame. Reddit pages on S•Town have astrolabe discussions. Websites promise to show you “How to Build an Astrolabe Like John B. McLemore From ‘S- Town’.” S•Town fans are turning up in museums asking to see astrolabes.

Visitors to Harvard’s museum are S•Town fans and want to see astrolabes.
Hey This American Life, perhaps you would like to do a whole show on astrolabes. While not as eccentric as John B. McLemore, I have built my own astrolabe, I know its history better than most, and I’m available. Your researcher/fact checker has my number. Have him give me a call.


  1. In talking to him, it seems he started with on-line resources, including my An Introduction to the Astrolabe.  ↩
  2. He probably used a euphemism, but somehow I think John B. McLemore would have preferred “died,” and I prefer it.  ↩
  3. And because I can’t just be late to the party, I find out late that I am late to the party, I learned about S•Town while listening to an old podcast of Wait Wait…Don’t Tell Me featuring Sarah Koenig[3a] that I had downloaded and then didn’t listen to for nearly a month. And even then I was in no hurry to listen to S•Town.  ↩

    3a. I should probably point out that the name Sarah Koenig meant nothing to me because I am one of perhaps only a handful of people, including John B. McLemore, who has never listened to Serial and only vaguely knows what it is.  ↩

  4. To be exact, Brian Reed’s description of the astrolabe comes at 44:05 into chapter 1. Astrolabes are mentioned in two other places: the first time is about 16 minutes into chapter 1; the last time is 2:35 into chapter 7. I don’t think I would say, as my friend did, that they “talk about astrolabes” in S•Town, but any popular culture reference is better than none.  ↩