Reasons for Astronomy in Early Societies

The calendarwhen to plantwhen will the rains come

Ceremonialssolstices and equinoxes

Astrology: positions of planet, Sun and Moon with respect to the constellations influence human events

Stonehenge: photograph by Frdric Vincent, March 2004

The Development of Mathematical Astronomy Islamic Astronomers

prepared by Ruth HowesMarquette University

with support from theWisconsin Space Grant Consortium

Alexander the Great from a mosaic at Pompei Downloaded from Wikipedia

Civilizations in Alexanders Empire with Mechanical Models of the UniverseIndia (used mathematical models andbase 10 number system)Babylon (used base 60 number system)SumariaEgyptGreece (used mathematical models and base 60 number system)and contact with China

Alexanders EmpireMaps from The World Factbook:http://www.cia.gov/cia/publications/factbook/index.html

Deferent:- planets circular orbit

Epicycle small sphere carrying the planet whose center moves along the deferent

* Sun

o Equant point about which the planetmoves with uniform speed Center of deferent Ptolemys 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 http://www-history.mcs.st-andrews.ac.uk/history/Quotations/Ptolemy.html

The Rise of Islam

622 A.D. Founding of Islam

A.D. Death of Mohammad

644 A.D. Islamic caliphs control much of Alexanders empire

786-809 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 IslamicManuscript viewOf epicyclic model.

Photo taken from medieval manuscript by Qotbeddin Shirazi, Persian Astronomer Downloaded from http://en.wikipedia.org/wiki/Islamic_science#Astronomy

Roots of Medieval Islamic Astronomy

Greece: geometry the use of algebra to describe geometryfractions in calculationsPtolemys model as improved by his successors

India:zerothe decimal pointthe sine function

Painting from Shahinshah-nama by Ala ad-Din Mansur-Sharazi written in honor of Sultan Murad III (1574-95) image downloaded from http://astrolabes.org/istanbul.htm courtesy of James E. MorrisonAstronomers at in the Court of Sultan Murad III

Contributions of Arabic Astronomers

writing down decimal calculations on paper

the cotangent functionproofs of theorems not known in Europe for centuries

development of instruments, notably the astrolabe

Image from a Soviet stamp found in Wikipediaal-Kwararizimi (d. 840)

Developed algebra bycombining Hindu and Greekwork. Used equations to describe geometric models in astronomy

Image downloaded from http://www-history.mcs.st-andrews.ac.uk/history/PictDisplay/Khayyam.html

Omar Khayyam (1038-1131)Best known for his poem, The Rubiyat alsoHeaded an observatory Developed an extremely accurate calendarCalculated 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 proofTusi couplealUrdis elimination of the equant from Ptolemys model

the Islamic astronomers never went heliocentric

Astronomy and Government were linked in medieval Islam

Ulugh Beg (1393-1449) grandson of Tamerlane and emperor

governor of Samarakand at 16construction of a madrasah at 24 (a think tank, a university and a religious school)

built an observatory at Samarakandbest astronomical tables of the dayUlugh calculated most accurate value of sin 1o

wrote poetry, studied philosophy

overthrown and killed by his son.

Stamps showing Ulugh Beg (1393-1449)Images from http://www-history.mcs.st-andrews.ac.uk/history/PictDisplay/Ulugh_Beg.htmlPortraits 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 http://www-history.mcs.st-andrews.ac.uk/history/Quotations/Ulugh_Beg.html

Ulugh Beg said:

Recent research is increasingly showing thatIslamic astronomers made significant advances from theirGreek 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.