Kevin Krisciunas writes on The Legacy of Ulugh Beg. Although he recognising the crucial role of Islamic observation, he still finds sources of disagreement with the notion that the Samarqand observatory exerted decisive influence on Europe.
Without going into the detail of such article, but just to add to some points already made, Krisciunas reminds us that Uluh Beg is to be remembered not for his princely role, but for his role as patron of astronomy, an astronomer, and observatory builder. His distinction was that he was one of the first to advocate and build permanently mounted astronomical instruments. The importance of his observatory is further enhanced by the large number of astronomers, between sixty and seventy, involved in observation and seminars. Of crucial importance, too, is that observations were carried on a systematic basis for lengthy periods of time, as from 1420 to 1437. The reason, as Krisciunas makes clear, why observations are not completed in one year but instead require ten or fifteen years, is:
`the situation is such that there are certain conditions suited to the determination of matters pertaining to the planets, and it is necessary to observe them when these conditions obtain. It is necessary, e.g., to have two eclipses in both of which the eclipsed parts are equal and to the same side, and both these eclipses have to take place near the same node. Likewise, another pair of eclipses conforming to other specifications is needed, and still other cases of a similar nature are required. It is necessary to observe Mercury at a time when it is at its maximum morning elongation and once at its maximum evening elongation, with the addition of certain other conditions, and a similar situation exists for the other planets.'
`Now, all these circumstances do not obtain within a single year, so that observations cannot be made in one year. It is necessary to wait until the required circumstances obtain and then if there is cloud at the awaited time, the opportunity will be lost and gone for another year or two until the like of it occurs once more. In this manner there is need for ten or fifteen years. One might add that because it takes Saturn 29 years to return to the same position amongst the stars (that being its period of revolution about the Sun), a period of 29 years might have been the projected length of the Samarkand programme of observations.'
In his article, Krisciunas, although recognising the crucial role of Islamic observation, still finds sources of disagreement with the notion that the Samarqand observatory exerted decisive influence on Europe. That, of course, is exactly the matter which plagues most minds of Western scholarship, refusing to acknowledge the Eastern impact (not just Islamic, but also Indian, and above all Chinese) on their civilisation. Krisciunas is not just one of the most fair minded, but also one of the most able scholars in the field. And his point of view has to be addressed on equal academic reasoning.
Kevin Krisciunas, writting on The Legacy of Uluh Beg, see: http://www.ukans.edu