مجله تاریخ علم
پیاپی 1 (پاییز 1382)

Le célèbre problème d’Archimède a conduit les mathématiciens islamiques à la résolution d’une équation cubique. Ils l’ont résolue finalement par les sectins coniques. Cependant, ils se contentaient de succès partiels, c’est-à-dire de la solution d’un problème géométrique. Omar Khayyām contrairement à ceux-ci, tout en abandonnant le problème en question s’attache aux équations cubiques pour elles-mêmes afin d’en donner une théorie consistante. Cette théorie se résume en représentation canonique des équations cubiques, arrangement homogénéisé des termes, résolutin géométrique à l’aide des sections contiques et discussion pour l’existence des racines. پ

There are many discrepancies and ambiguities in the ideas of the researchers relating to the appearance and development of the lunar Hegira calendar in the Arabic peninsula during the first 18 years after the Emigration of H.H.Mohammad the Prophet. From the middle of the 2nd century of the Hejira era up to now, investigations have been carried out about the lunar Hejira calendar. Several tables and calculation methods have been provided for this purpose. However, they do not solve the problem satisfactorily. On this basis, I have prepared a computerized mathematical model for the subject which has led to two equations for the calculation of the conventional lunar Hegira calendar. These equation may be used for any year after the Hejira era and enable us to determine the leap years, the year-days and the week-days.

The invention and fabrication of the precise mechanical clocks for reckoning the time correctly, dates back to about three hundred years ago. As such, the mean or actual length of tropical years measured in the ancient history might have been also based on the time measured by sundial which measures solar apparent (real) time based on the length of apparent (real) solar day. The length of real solar day itself changes slightly throughout the year. At the present time, precision and accuracy in the measurement of time has reached to surprising limits which has revealed the extremely small changes in the period of rotational and ephemeris time. The Iranian calendar in vogue is a solar one based on the actual length of each tropical year from equinox to equinox. The leap years are set based on the time when equinox occurs in comparison to the time of the real solar noon for longitude 52.5 degrees east. As such, one has to pay attention to the exact changes in the time of the real solar noon in the distant past and future.There are two schools of thought about the determination of leap years which happens each four or occasionally five years.Based on the changing effect of the length of the actual tropical year, many scholars believe that there is no exact rule for the settlement of leap years. On the other hand, some others believe that it is possible to adopt a certain rule for the determination of leap years, namely in a 2820-year cycles. As such, it is believed that the equinox happens exactly at the same time after 2820 years and this cycling rule is going on.This article deals with a discussion about the proposed 2820-year cycle and the scientific and historical implications involved therewith.As such, the necessity for an extensive reasearch study to be carried out about the proposed cycle in highlighted.

The Survey of Islamic astronomical tables (zījes) is a necessary work. In this field, one of the most important projects is providing of the astronomical tables catalogues. The oldest astronomical tables catalogue has been written in 19thcentury, but the best Islamic astronomical tables catalogue is A Survey of Islamic Astronomical Tables written by E.S. Kennedy. This book has been written several years ago and now, it is necessary to review this. This research project is a supplement to this book. I tried to gather the bibliography of astronomical tables which kennedy did not write them in his book. Since this project is done in Iran, I mostly tried to find astronomical tables which are exsist in Iran. In overvall, the kennedy’s guess, which the number of astronomical tables is about 250, is accepted by this article.

In the middle Priodof Islamic astronomy, the Mu‘tabarSanjarīZīj was composed by the Iranian astronomer ‘Abd al-Rahmān al-Khāzinī (fl.475-525 A.H./1082-1130 A.D) who lived in Marw. In his introductin to his zīj he remarks that made observations for 35 years to prepare it, and he lists his innovations, especially in the field of lunar crescent visibility and in the theory of eclipse, then he demonstrates its superiority over pervious zījes in general.In this paper I present a summery of some important sections of thiszīj, and I mention the extant mss.thereof. Of course each section will need a separate through study. Despaite its importance, the Sanjarīzīj has scarcely been considered in detail by modern science historians, and its whole text has not been published yet.

This is an edition of an Arabic treatise composed by the eminent Iranian astronomer and mathematician ‘Abd al-Rahmān al-Sūfī (d. 376 A.H./986 C.E.), mostly known for his famous book Suwar al-kawākib (“The constellations”). Entitled Risālafī ‘amal al-ashkāl al-mutasāwiyat al-adlā‘ Kullahā bi-fathatwāhida (“Treatise on the construction of regular polygons by [compasses of] fixed opening”), it was written on the request of the local ruler ‘Adad al-DawlaDeilami. The present edition has been made using two mss.extant in the Holy Shrine library (Mashhad, IRAN): MS 5535 (copied in 1286 A.H.) and MS 12121 (copied in 1308 A.H.), both copied from a ms. dated 688 A.H. copied in Maragha. The first ms. has been the basis of our work. Addition for reconstruction of the text, including those taken from the second ms. are given in brackets: [].