Article:
Zij al-Sindhind
By Muhammad ibn Ibrahim al-Fazari

..."Of particular interest is the well told story of the Indian scholar who traveled to Baghdad, at the behest of Caliph al-Mansur (early ruler of the Arab Empire). R Gupta reports the story as such:

...In the year 156 (772/773 AD) there came to Caliph al-Mansur a man (an Ujjain scholar by the name of Kanka) from India, an expert in hisab (computation) bringing with him a work called Sindhind (i.e. Siddhanta) concerning the motions of the planets. [RG, P 12]"

700-825 A.D.
The period of assimilation and syncretisation of earlier Hellenistic, Indian, and Sassanidastronomy. The first astronomical texts that were translated into Arabic were of Indian and Persian origin. The most notable of the texts was Zij al-Sindhind, an 8th-century Indian astronomical work that was translated by Muhammad ibn Ibrahim al-Fazari and Yaqub ibn Tariq after 770 CE under the supervision of an Indian astronomer who visited the court of caliph Al-Mansur in 770. Another text translated was the Zij al-Shah, a collection of astronomical tables (based on Indian parameters) compiled in Sasanid Persia over two centuries. Fragments of texts during this period indicate that Arabs adopted the sine function (inherited from India) in place of the chords of arc used in Greek trigonometry.

Read more:

http://bit.ly/18bKMQO