Ghāzān Khān's Astronomical Innovations at Marāgha Observatory

摘要

Everything we know about the observatory in Tabriz founded by Ghāzān Khān (r. 1271-1304), the seventh ruler of the Ilkhānid dynasty of Persia (1295-1304), was published by Ayd?n Say?l? some fifty years ago.~1 Relying on primary historical sources, he presented an adequate description of its astronomical activities and of the many skills of Ghāzān Khān in the field of observational instrumentation.~2 Say?h also presented a good overview of the Marāgha observatory from 1260-1283,~3 but due to a lack of reliable evidence for the period after ca. 1280, he made some statements-especially concerning Ghāzān Khān's astronomical innovations-that could not be substantiated. A recently discovered treatise has now revealed the exact type and location of Ghāzān Khān's innovations, which we enumerate below. Our treatise begins where Say?l? left off and appears to give dependable information that we can use to illuminate the later period at the Marāgha observatory, during which very little is known concerning the type and extent of astronomical activity.