It is interesting that those phenomena, either directly or indirectly, are in relation with the two periods of scientific activities at the Maragha Observatory (AD 1259-1283, 1283-ca.
June 1283 AD) was a prominent astronomer of the first period of Maragha Observatory.
2) Sayi1i also presented a good overview of the Maragha observatory from 1260-1283, (3) but due to a lack of reliable evidence for the period after ca.
The Maragha observatory was built in 1259 by Hulegu (d.
astrolabes) of which a variety of models are known and plenty of examples are extant, observational instruments before the founding of the Maragha observatory appear to have been large models of instruments known from classical times, modified to a certain degree, and named after patrons.
In this article we have presented an anonymous Persian treatise about the instruments of the second period of the Maragha observatory, built under the supervision of Ghazan Khan.
The treatise substantiates a hitherto unproven historical claim by Rashid al-Din Tabib that Ghazan Khan was the inventor of several "new" astronomical instruments, which, as we discussed above, were installed during what we have termed the second period of the Maragha observatory.
In addition, there appears to be continuity or succession for a few instruments after the second period of the Maragha observatory, notably the geometrical square which appeared in Europe in the mid-fifteenth century.
And in the early 16th century, these came from Iraq, where the Maragha School, a group of Arab scholars named for the Maragha observatory
in the arid mountains of western Iran, had for centuries produced the most accurate mathematical updates to the standard Ptolemaic model of planetary motion.