The historical navigation device in yesterday’s post was too newfangled for the conquistadors.This is what they would have used: a historic astrolabe from 1400, just in time for the conquistadors. This historical model isn’t quite intended for use on a boat at sea, but the ones used by sailors were similar if less visually appealing. The concept is the same as yesterday’s sextant. This is essentially an ancient GPS, except this device is harder to get an accurate reading from. As we learned with some early problems with Apple Maps, then, as now, accurate data is required to convert the measurements into a position at sea.
For use at sea, the astrolabe needs to be suspended by a string so that it stays level on a heaving ship deck, which creates problems on windy days. Just as with yesterday’s sextant, the idea is to measure the angle between the sun or stars and the horizon, and then use the current day/time (if you know it accurately), mathematical tables, and/or multiple measurements to get a position through a complex mathematical recipe. Historically, navigation with an astrolabe or sextant was complicated! And you thought Apple Maps had problems. 🙂 We still haven’t explained what this has to do with Carl Sagan, or theories about the conquistadors in recent TV documentaries.
Stay tuned as we continue our story of civilization and data.
Photo credit: Wikimedia/Sage Ross/CC-BY-SA-3
A version of this article originally appeared as a photo post on our Instagram feed.