Transcript Islamic Astronomy

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:http://www.cia.gov/cia/publications/factbook/index.html
Deferent:- planet’s
circular orbit
Ptolemy’s Cosmology
Epicycle –small sphere
carrying the planet
whose center moves
along the deferent
*
·
o
* Sun
o Equant – point about
which the planet
moves with
uniform speed
·
Center of deferent
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
632 A.D.
Death of Mohammad
644 A.D.
Islamic caliphs control much of
Alexander’s 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 Islamic
Manuscript view
Of 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 geometry
fractions in calculations
Ptolemy’s model as improved by his successors
India:
zero
the decimal point
the sine function
Astronomers at in the
Court of Sultan Murad III
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. Morrison
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
al-Kwararizimi (d. 840)
Developed algebra by
combining Hindu and Greek
work. Used equations to
describe geometric models
in astronomy
Image from a Soviet stamp found in Wikipedia
Omar Khayyam
(1038-1131)
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
Image downloaded from
http://www-history.mcs.st-andrews.ac.uk/history/PictDisplay/Khayyam.html
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 (1393-1449) 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 1o
wrote poetry, studied philosophy
overthrown and killed by his son.
Portraits of Ulugh Beg
Stamps showing Ulugh Beg (1393-1449)
Images from http://www-history.mcs.st-andrews.ac.uk/history/PictDisplay/Ulugh_Beg.html
Ulugh Beg said:
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.standrews.ac.uk/history/Quotations/Ulugh_Beg.html
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.