Abū Isḥāq Ibrāhīm ibn Yaḥyā al-Naqqāsh al-Zarqālī al-Tujibi[2] (Arabic: إبراهيم بن يحيى الزرقالي); also known as Al-Zarkali or Ibn Zarqala (1029–1100), was an Arab maker of astronomical instruments and an astrologer from the western part of the Islamic world.

He is known to have taught and visited Córdoba on various occasions, and his extensive experience and knowledge eventually made him the foremost astronomer of his time.

In his "De Revolutionibus Orbium Coelestium", in the year 1530, Nicolaus Copernicus quotes the works of al-Zarqali and Al-Battani.

[10] Al-Zarqālī wrote two works on the construction of an instrument (an equatorium) for computing the position of the planets using diagrams of the Ptolemaic model.

He also invented a perfected kind of astrolabe known as "the tablet of al-Zarqālī" (al-ṣafīḥā al-zarqāliyya), which was famous in Europe under the name Saphaea.

[13] According to a report found in al-Zuhrī's Kitāb al-Juʿrāfīyya, his name is given as Abū al-Qāsim bin ʿAbd al-Raḥmān, also known as al-Zarqālī, which has made some historians think that this is a different person.

[14] Al-Zarqālī's model for the motion of the Sun, in which the center of the Sun's deferent moved on a small, slowly rotating circle to reproduce the observed motion of the solar apogee, was discussed in the thirteenth century by Bernard of Verdun[15] and in the fifteenth century by Regiomontanus and Peurbach.

In the sixteenth century Copernicus employed this model, modified to heliocentric form, in his De Revolutionibus Orbium Coelestium.

[18] This almanac that he compiled directly provided "the positions of the celestial bodies and need no further computation", it further simplifies longitudes using planetary cycles of each planet.