Reasons for Astronomy in Early Societies The calendar when to plant when will the rains come Ceremonials solstices and equinoxes Astrology: positions of planet, Sun and Moon with respect to the constellations influence human events

Stonehenge : photograph by Frédéric Vincent, March 2004

The Development of Mathematical Astronomy Islamic Astronomers prepared by Ruth Howes Marquette University with support from the Wisconsin Space Grant Consortium

Alexander the Great from a mosaic at Pompei Downloaded from Wikipedia

Civilizations in Alexander’s Empire with Mechanical Models of the Universe India (used mathematical models and base 10 number system) Babylon (used base 60 number system) Sumaria Egypt Greece (used mathematical models and base 60 number system) and contact with China

Alexander’s Empire Maps from The World Factbook:

* · o Deferent:- planet’s circular orbit Epicycle –small sphere carrying the planet whose center moves along the deferent * Sun o Equant – point about which the planet moves with uniform speed · Center of deferent Ptolemy’s Cosmology

Ptolemy said: When I trace at my pleasure the windings to and fro of the heavenly bodies, I no longer touch the earth with my feet: I stand in the presence of Zeus himself and take my fill of ambrosia, food of the gods. Quoted in C B Boyer, A History of Mathematics (New York 1968) and found on

The Rise of Islam 622 A.D. Founding of Islam 632 A.D. Death of Mohammad 644 A.D. Islamic caliphs control much of Alexander’s empire A.D. Caliph Harun al-Rashid rules from Greece to India from Baghdad translates books including astronomy

Importance of Astronomy to Islam Quibla – the direction of Mecca which must be faced during 5 daily prayers Calendar – lunar; determines times of religious observances, most importantly Ramadan – the month of fasting Days begin at sunset. Months begin with first sighting of crescent moon in western sky And (against Islam!) many caliphs practiced astrology

Medieval Islamic Manuscript view Of epicyclic model. Photo taken from medieval manuscript by Qotbeddin Shirazi, Persian AstronomerQotbeddin ShiraziPersian Downloaded from

Roots of Medieval Islamic Astronomy Greece: geometry the use of algebra to describe geometry fractions in calculations Ptolemy’s model as improved by his successors India:zero the decimal point the sine function

Painting from Shahinshah-nama by ‘Ala ad-Din Mansur-Sharazi written in honor of Sultan Murad III ( ) image downloaded from /istanbul.htm courtesy of James E. Morrison /istanbul.htm Astronomers at in the Court of Sultan Murad III

Contributions of Arabic Astronomers writing down decimal calculations on paper the cotangent function proofs of theorems not known in Europe for centuries development of instruments, notably the astrolabe

Image from a Soviet stamp found in Wikipedia al-Kwararizimi (d. 840) Developed algebra by combining Hindu and Greek work. Used equations to describe geometric models in astronomy

Image downloaded from Omar Khayyam ( ) Best known for his poem, The Rubiyat also Headed an observatory Developed an extremely accurate calendar Calculated the length of the day correctly to the sixth decimal point

Copernicus and the Islamic Astronomers probably knew their work from time in northern Italy cited al-Battani 23 times in De revolutionibus orbium coelestium used two theorems without proof Tusi couple al’Urdi’s elimination of the equant from Ptolemy’s model the Islamic astronomers never went heliocentric

Astronomy and Government were linked in medieval Islam Ulugh Beg ( ) grandson of Tamerlane and emperor governor of Samarakand at 16 construction of a madrasah at 24 (a think tank, a university and a religious school) built an observatory at Samarakand best astronomical tables of the day Ulugh calculated most accurate value of sin 1 o wrote poetry, studied philosophy overthrown and killed by his son.

Stamps showing Ulugh Beg ( ) Images from Portraits of Ulugh Beg

It is the duty of every true Muslim, man and woman, to strive after knowledge. [quoting the Hadith. Inscribed on his gate in Bukhara, 1417] found on andrews.ac.uk/history/Quotations/Ulugh_Beg.htmlhttp://www-history.mcs.st- andrews.ac.uk/history/Quotations/Ulugh_Beg.html Ulugh Beg said :

Recent research is increasingly showing that Islamic astronomers made significant advances from their Greek and Indian predecessors. Islamic astronomy certainly influenced the development of Astronomy around the time of Copernicus. It remains to be seen exactly how that influence occurred. Current thinking has increased its role and newly discovered and translated manuscripts continue that trend.