Al-Urdi's Article on 'The Quality of Observation'

Astronomy has for a long time been of keen interest of Muslims throughout centuries. This article by Professor Sevim Tekeli highlights the quality and precision of observations made by al-Urdi.

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Figure 1. A depiction of the Maragha Observatory.

See the link below  to the full article if you need to obtain PDF reading softwareThis short article is taken from the full article (by Prof. Sevim Tekeli) which is available here as 53 page PDF file.

This article includes the critical edition and the translation of the Risala fî kayfiya al-arsâd wa ma yuhtaja ilâ llmihi wa amalihi min turuq al-muwaddiya ild marifa'auddt al-kawakib (The treatise on the quality of the observations and the theoretical and practical knowledge needed to make them, and the methods leading to understanding of the regularities of the stars) of Al-Urdî. It gives us a whole description of the instruments of the Maragha Observatory that was constructed by Nasir al-Din al-Tûsî in 1261 under the auspices of Hulagu. Only at the time of Tycho Brahe (in 16th century) did the instruments in Europe become as perfect and precise as the instruments constructed in the Maragha Observatory.

Al-'Urdî is a Syrian architect. He constructed the water installations of Damascus. He has also constructed astronomical instruments for Al-Mansur, the ruler of Hims. After 1259, he worked in cooperation with Nasir al-Din al-Tûsî.

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Figure 2. Nasir al-Din al-Tusi – commemorated on an Iranian stamp upon the 700th anniversary of his death.

We could clearly see from the descriptions given in this article that the construction of the instruments and their formations were done with great care in order to have accurate results.

An incomplete French translation of this article was made by Amabl Jourdain (in 1909) in Mémoire sur L'observatoire de Meragah et sur quelques instruments emploiyés poury observer. In 1928, it was translated into German by Hugo Seemann as Die
Instrumente der Sternwarte zu Maragha nach den Mitteilungen von Al- Urdî. This German translation is quite complete. Though it is one of the fundamental books in Islamic Astronomy, its text has not been published up to now. The text herein is the comparison of the three manuscripts. Two of these three copies are in Istanbul and the other one is in Paris.

Though the date of the transcription has not been indicated in the manuscripts we can easily deduce from the information given in the text that it has been written after the construction of the Maragha Observatory and before the death of Nasir al-Din Tûsî. In the text, the date of the construction of the instruments is given as 1261/2. Since Nasir al-Din Tûsî died in 1274, we can estimate easily that the manuscript was transcribed between 1262 and 1274. However, since Al-'Urdî indicates that some of the models of the instruments have already been constructed but without saying whether they have been constructed in the Observatory or not, we can make our estimations further than 1274.

According to the grammar rules, it is necessary to accord the verbs but in addition, accords were made in the kind and number of verbs, when this is not conational in order to provide precision and these changes are indicated with notes. The errors thus made in the dictation are different in the manuscripts but still these changes do not require any corrections.

The translation of the manuscript was made word for word. It has been compared to the German translation and the differences were noted. But towards the end of the German translations more emphasis was given to the meaning without a literal translation. That is why the differences were not noted separately.

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