Treatise on Astrology of the Kaiyuan Era

The Treatise on Astrology of the Kaiyuan Era is a astrology encyclopedia compiled by the lead editor Gautama Siddha and numerous scholars from 714 to 724 AD during the Kaiyuan era of Tang Dynasty. The compilation is attributed to the author by 729. Its full title is regarded as the Great Tang Treatise on Astrology of the Kaiyuan Era. It is also referred to as the Kaiyuan Star Observations.

The book

The book is divided into 120 volumes and consisted of about 600,000 words. The compilation of writings had based on many previously astrological and divination materials, and probably a similar classic known as the ''Yisizhan'', compiled by Li Chunfeng approximately in 645. It incorporated many fragments works, including the star catalogues of Shi Shen and Gan De, and contained a translated version of Navagraha calendar under the chapter of 104. The astronomical table of by the and , Aryabhata, were also translated into the ''Kaiyuan Zhanjing''.

The manuscript had started to fade away in copies since the 10th century, but was over again received a special attention by scholar Cheng Mingshan in 1616 and was later included in the Siku Quanshu collections of the 18th century.