Toledan Tables

The Toledan Tables, or Tables of Toledo, were astronomical tables which were used to predict the movements of the Sun, Moon and planets relative to the fixed stars. They were completed around year 1080 by a group of Arabic astronomers at Toledo, Spain. They had started as preexisting Arabic tables made elsewhere, and were numerically adjusted to be centered on the location of Toledo. In modern English astronomy, tables of movements of astronomical bodies are called ephemerides.

The Tables of Toledo were partly based on the work of al-Zarqali (known to the West as Arzachel), an Arab mathematician, astronomer, astronomy instrument-maker, and astrologer, who lived in Toledo. The tables were produced by a team whose membership is largely unknown, with the exception of al-Zarqali. Toledo came under Christian Spanish rule in the mid-1080s, shortly after the tables were completed. A century later at Toledo, the Arabic-to-Latin translator Gerard of Cremona (1114–1187) translated for Latin readers the Tables of Toledo, the most accurate compilation in Europe at the time. During the mid-thirteenth century, Campanus of Novara constructed tables for the meridian of Novara from the Toledan tables of al-Zarqali.

The Toledan Tables were updated in the 1270s by the Alfonsine tables, which were produced at Toledo, in Spanish and Latin, from the original tables of two centuries earlier. The descendants of the Toledan Tables, as updated with some corrections, were the most widely used astronomy tables in late medieval Latin astronomy. Although the compilers of the tables assumed the Earth was stationary at the center of the universe, the data in the tables was successfully used by Copernicus in the development of the model in which the Sun is stationary.

See also

• Zij (medieval Arabic astronomy tables)
• Alfonsine tables (produced at Toledo, mostly the original Toledan Tables)
• Prutenic Tables (first comprehensive heliocentric tables, year 1551)
• Rudolphine Tables (astronomy tables of Kepler, year 1627)