The Zij-i-Sultani is generally considered[citation needed] the most accurate and extensive star catalogue up to its time, surpassing its predecessors, including Ptolemy's work, Abd al-Rahman al-Sufi's Book of Fixed Stars, and the Maragheh observatory's Zij-i Ilkhani. It was not surpassed until the work of Taqi al-Din and Tycho Brahe in the 16th century.