Islamic Astronomy and Geography
David A. King
- 428 pages
- English
- ePUB (mobile friendly)
- Available on iOS & Android
Islamic Astronomy and Geography
David A. King
About This Book
This volume of 12 studies, mainly published during the past 15 years, begins with an overview of the Islamic astronomy covering not only sophisticated mathematical astronomy and instrumentation but also simple folk astronomy, and the ways in which astronomy was used in the service of religion. It continues with discussions of the importance of Islamic instruments and scientific manuscript illustrations. Three studies deal with the regional schools that developed in Islamic astronomy, in this case, Egypt and the Maghrib. Another focuses on a curious astrological table for calculating the length of life of any individual. The notion of the world centred on the sacred Kaaba in Mecca inspired both astronomers and proponents of folk astronomy to propose methods for finding the qibla, or sacred direction towards the Kaaba; their activities are surveyed here. The interaction between the mathematical and folk traditions in astronomy is then illustrated by an 11th-century text on the qibla in Transoxania. The last three studies deal with an account of the geodetic measurements sponsored by the Caliph al-Ma'mûn in the 9th century; a world-map in the tradition of the 11th-century polymath al-Bîrûnî, alas corrupted by careless copying; and a table of geographical coordinates from 15th-century Egypt.
Frequently asked questions
X
Too Many Cooks … A New Account of the Earliest Muslim Geodetic Measurements
Introduction
q | qibla (local direction of Mecca, measured from the local meridian) |
L | terrestrial longitude |
ΔL | longitude difference from Mecca |
ΔLB | longitude difference between Baghdad and Mecca |
Δϕ | latitude difference from Mecca |
ΔϕB | latitude difference between Baghdad and Mecca |
ϕ | latitude |
ϕB | latitude of Baghdad |
ϕM | latitude of Mecca. |
1. Ibn Yūnus’ account
Discussion of the (distances in) cubits between places: Sanad ibn ʿAlī mentioned in a statement of his which I found that al-Ma’mūn ordered Khālid ibn ʿAbd al-Malik al-Marwarrūdhī and him to measure the amount of one degree of a great circle on the surface of the earth. He said: “We both set off together for this (purpose). (al-Ma’mūn) ordered ʿAlī ibn ʿĪsā al-Asṭurlābī and ʿAlī ibn al-Buḥturī to do the same and they went off in a different direction.” Sanad ibn ʿAlī said: “Khālid ibn ʿAbd al-Malik and I travelled to (a place) between W’mxh12 and Tadmur ( = Palmyra) and there we measured the amount of a degree of a great circle on the surface of the earth. It was fifty-seven miles (mīl). ʿAlī ibn ʿIsā and ʿAlī ibn al-Buḥturī also made measurements and the two of them found the same as this. The two reports from the two directions (telling of) the two measurements with the same result arrived at the same time.”Aḥmad ibn ʿAbdallāh, known as Ḥabash, stated in his book in which he mentioned the observations (of the compilers) of the Mumtaḥan (Zīj) in Damascus, that al-Ma’mūn ordered that one degree of a great circle on the surface of the earth should be measured. He said: “They set off for this (purpose) in the desert of Sinjār, (travelling) until two measurements of the meridian altitude on the same day differed by one degree, and then they measured the distance between the two places, and it was 56 and one-quarter miles, where each mile is four thousand cubits, these being the “black cubits” that were adopted by al-Ma’mūn.”