Astronomy · a Light

A Toledo instrument maker ended up correcting Ptolemy

Al-Zarqali began as a metalworker in Toledo, making instruments to order for the astronomers of the city, who noticed how well he understood what he was building and gave him books. He went on to lead the group that produced the Toledan Tables around 1070. Translated into Latin, those were the tables Europe used for two centuries, until the Alfonsine Tables replaced them, and those were compiled in the same city. He tracked the slow drift of the point where the sun is furthest from the earth, which al-Battani had shown was moving but had not measured. He also designed an astrolabe plate that works at any latitude, as did a contemporary in Toledo, so a traveller no longer needed a separate disc for every city.

Al-Zarqali · Toledo, c. 1029-1100