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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.
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