3 ms·

An accident of lighting uncovers origins of the astrolabe

85 points by jnord 2y ago

abecedarius 2y ago
The retitle of the submission is misleading. The article's about one particular astrolabe, not about the invention.
- mateus1 2y ago
  Yes, I was confused while reading the article. Cool story nonetheless
- jcd000 2y ago
  Yup, the title is clickbaity, but the actual article interesting.
bunabhucan 2y ago
Original paper: >With its provenance, this astrolabe is one of the earliest Islamic astrolabes documented in early modern Italy still preserved today. ... >The astrolabe is Andalusian, and from the style of the engraving and the arrangement of the scales on the back, it can be compared to instruments made in Spain in the eleventh century. The astrolabes made in Toledo by Ibrāhīm ibn Saʿīd al-Sahlī during the period of the Taifa (ca. AD 1018–1085) present similarities... https://brill.com/view/journals/nun/39/1/article-p163_9.xml https://brill.com/view/journals/nun/39/1/article-p163_9.xml
dieselgate 2y ago
Super cool article. My grandmother is from Spain and it’s fascinating to learn more about history from this time period. A cousin once took me to the military Maritime museum in Madrid and there’s a lot to mull over regarding the scientific/technology priorities of like, 600 to 1000 years ago. Writing this on a sailboat right now, with gps and internet, crazy how quickly things change but also stay the same Edit: it’s also so fascinating how the unit was altered over time and re-enscribed/calibrated. Hardware updates! Reminds me of some posts recently about imaging ancient scrolls and reading the original but erased text/script
- 082349872349872 2y ago
  > how quickly things change but also stay the same As it'd be foolish to rely on things like gps that may no longer be around when you want/need to launch, as far as I know ICBMs (and presumably also SLBMs?) still shoot the stars near apogee, to fix their reckoning.
  - mistrial9 2y ago
    Agree that non-electronic, non-networked navigation has a place but marine conditions often obscure the skies in this area of the world.. also the on-demand precision of modern times gets to be "required" for various interactions with other humans and their territory.
  - adolph 2y ago
    For more information: The astro-nav's gimbaled telescope-like system on top of the guidance group works by making an ever-widening circular search pattern to find and fix three of any of 64 mapped stars in its memory, and compares their locations to a Julian calendar and a highly accurate chronometer. https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-winning-future-fights-in-gps-denied-environments https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-w... https://timeandnavigation.si.edu/multimedia-asset/nortronics-nas-14v2-astroinertial-navigation-system https://timeandnavigation.si.edu/multimedia-asset/nortronics...
mnw21cam 2y ago
It's the "precession of the equinoxes", not the "procession of the equinoxes".
- 082349872349872 2y ago
  Wait long enough, and even the ruling gods may need to be recalibrated with the changing equinoxes: https://news.ycombinator.com/item?id=38761574 https://news.ycombinator.com/item?id=38761574

85 points by jnord 2y ago

abecedarius 2y ago

The retitle of the submission is misleading. The article's about one particular astrolabe, not about the invention.

mateus1 2y ago
Yes, I was confused while reading the article. Cool story nonetheless
jcd000 2y ago
Yup, the title is clickbaity, but the actual article interesting.

bunabhucan 2y ago

Original paper: >With its provenance, this astrolabe is one of the earliest Islamic astrolabes documented in early modern Italy still preserved today. ... >The astrolabe is Andalusian, and from the style of the engraving and the arrangement of the scales on the back, it can be compared to instruments made in Spain in the eleventh century. The astrolabes made in Toledo by Ibrāhīm ibn Saʿīd al-Sahlī during the period of the Taifa (ca. AD 1018–1085) present similarities... https://brill.com/view/journals/nun/39/1/article-p163_9.xml https://brill.com/view/journals/nun/39/1/article-p163_9.xml

dieselgate 2y ago

Super cool article. My grandmother is from Spain and it’s fascinating to learn more about history from this time period. A cousin once took me to the military Maritime museum in Madrid and there’s a lot to mull over regarding the scientific/technology priorities of like, 600 to 1000 years ago. Writing this on a sailboat right now, with gps and internet, crazy how quickly things change but also stay the same Edit: it’s also so fascinating how the unit was altered over time and re-enscribed/calibrated. Hardware updates! Reminds me of some posts recently about imaging ancient scrolls and reading the original but erased text/script

082349872349872 2y ago
> how quickly things change but also stay the same As it'd be foolish to rely on things like gps that may no longer be around when you want/need to launch, as far as I know ICBMs (and presumably also SLBMs?) still shoot the stars near apogee, to fix their reckoning.
- mistrial9 2y ago
  Agree that non-electronic, non-networked navigation has a place but marine conditions often obscure the skies in this area of the world.. also the on-demand precision of modern times gets to be "required" for various interactions with other humans and their territory.
- adolph 2y ago
  For more information: The astro-nav's gimbaled telescope-like system on top of the guidance group works by making an ever-widening circular search pattern to find and fix three of any of 64 mapped stars in its memory, and compares their locations to a Julian calendar and a highly accurate chronometer. https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-winning-future-fights-in-gps-denied-environments https://www.twz.com/17207/sr-71s-r2-d2-could-be-the-key-to-w... https://timeandnavigation.si.edu/multimedia-asset/nortronics-nas-14v2-astroinertial-navigation-system https://timeandnavigation.si.edu/multimedia-asset/nortronics...

mnw21cam 2y ago

It's the "precession of the equinoxes", not the "procession of the equinoxes".

082349872349872 2y ago
Wait long enough, and even the ruling gods may need to be recalibrated with the changing equinoxes: https://news.ycombinator.com/item?id=38761574 https://news.ycombinator.com/item?id=38761574