One of the important scientists working in the Merâga and Tabriz observatories during the Ilkhanians Period is also Shams al-Dîn al-Wâbkanawî al-Bukharî. Shams al-Dîn al-Wâbkanawî al-Bukharî, who conducted astronomy and observation studies for 40 years since 1272, is the owner of Zij-i al-Muhaqqaq alSultanî, which he started writing in Sultân Uljaytu Khan Era. However, despite the beginning of the writing of this Zîj Olcaytu Han Period (1304-1316), upon his death, he was dedicated to his son, Ilhanli ruler Ebu Sa’id Bahadır (1317-1335). The most important characteristic of Zij-i al-Muhaqqaq al-Sultanî is; Zijs, which was written before, but was lost in time, is mentioned in this work, and Zij-i İlkhanî, who was alleged to have had some mistakes in it and who wrote it on the basis of previous Zijs, is criticizing and giving the original observations to justify these criticisms. Shams al-Dîn al-Wâbkanawî al-Bukharî is another development which makes important in the history of astronomy, 30 January 1283, the "the annular eclipse" is to give information about. İn addition, outside the establishment of observatories in Maragha in the Hulagu Khan Period (1256- 1265) and in Tabriz in the Ghâzân Khan Period (1295-1304). It is even estimated that Shams al-Dîn alWâbkanawî al-Bukharî worked in this observatory, which was allegedly founded in Sultaniyye during the Sultan Uljaytu Khan period (1304-1316). [ABSTRACT FROM AUTHOR]