Al-Zarqali
Andalusian astronomer and instrument maker who invented the universal astrolabe and improved astronomical tables.
Who or what
Abu Ishaq Ibrahim ibn Yahya al-Zarqali (also known as Zarqali or Arzaquiel, 1028–1087) was a leading Andalusian astronomer and instrument maker based in Toledo.
He built and designed precision instruments, most notably the "saphea" (universal astrolabe plate) that worked at any latitude.
Why it mattered
Al-Zarqali was the first to prove that the motion of the solar apogee relative to the fixed stars is not constant — a challenge to Ptolemaic astronomy.
His instruments were so precise they were used for centuries across Europe and the Islamic world.
Key works and moments
His Toledan Tables (based on extensive observations) were the most accurate astronomical tables in Europe for over 200 years.
The saphea (safiha) astrolabe could be used at any latitude without changing the plate, a major innovation over earlier instruments.
Further detail
He determined the rate of the solar apogee's motion as 12.04 seconds of arc per year (modern: 11.8'').
His data on the obliquity of the ecliptic gave 23\u00b033' (compared to Ptolemy's 23\u00b051').
Legacy
The Toledan Tables were translated into Latin and used by Copernicus and other European astronomers.
His astrolabe designs influenced instrument makers across Europe and the Islamic world for centuries.
More in Islamic Golden Age
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