1) During the Abbasid Caliphate from 750-1258 CE, astronomy flourished in the Islamic world with the establishment of observatories and houses of wisdom where scholars studied the field. 2) Key Muslim astronomers and mathematicians like al-Khwarizmi, al-Battani, and al-Biruni made advances in determining the size of the earth, accurately calculating the length of the solar year, and developing early astronomical instruments and models of the solar system. 3) Later astronomers such as al-Zarqali, al-Tusi, and Ulugh Beg established additional observatories where further observations and studies were conducted.

1. Astronomy

2. Al-Quran:
By Sun , Muslims
Calculate times for
Prayer
By Moon, Muslims
determined a lunar
calendar

3. Abbasid Caliphate (750 - 1258)
Astronomy started among the Muslims during this period
Caliph Harūn (763-809)

4. The Darul Hikima (House of Wisdom) founded by
Mamun-ur-Rashid in Baghdad housed some of the
most eminent scholars of Astronomy
Caliph Mamun ar Rashid (786-833 A.D) House of wisdom Baghdad (8th Century)

5. The Arabs were the first to build observatories
During the reign of Mamun

6. Abu Abdullah Muhammad
ibn Musa al-Khwarizmi
(Persia 780 –850A.D)
• Mathematician
• Astronomer
• Geographer
Statue in Tehran

7. Khwarizmi successfully determined the
size & circumference earth

8. Used for computational
purposes
Eliminates the need for
calculations in measurements
Khwarizimi invented Quadrant

9. Sine Quadrant was invented by Khwarizimi
Used for accurate
timekeeping by
the Sun and Stars,
and could be
observed from any
latitude
Sine Quadrant

10. Ibrahim al-Fazari (b. 796) was the first Muslim
in 8th century A.D to construct an “Astrolabe”

11. Al Battani (born in Turkey in 858– died in 929 A.D)
accurately determined the solar year as being
365 days, 5 hours, 46 minutes and 24 seconds

12. Abul Hasan Mesudi ( b. 896, Baghdad, d. 956, Cairo, Egypt )
AL-Mesudi invented Telescope

13. Abul Wafa ( 939 - 998 khorasan )
Introduced the use of the secant as well as the
tangent into astronomical observations
Tangent
Secant
Abu Wafa (Khorasan)

14. Al-Biruni (973 -1048 A.D Ghazni)
First to conduct experiment related to astronomy
He established the
fact by
experimentation
that that everything
attracts toward the
center of the earth

15. Al Biruni famous diagram
showing different phases of moon indicates the moon
revolving around earth and the earth revolving around the sun

16. Abu Rayhan al-Biruni
He invented Planisphere
• The earliest star chart
• An early analog
computer
• “Qanun-i-Masoodi”
discusses Planisphere

17. .
Al-Biruni’s
mechanical lunar solar calendar computer
fixed-wired
knowledge
processing machine

18. Abu Ishaq Ibrahim al-Zarqali
Astronomer
Mathematician
(Andalus,1029 – 1087)

19. AL-Zarqali invented The Equatorium
A mechanical device for
finding the longitudes and
positions of the Moon,
Sun, and planets without
calculation using a
geometrical model
The Equatorium

20. Al-Zarqali constructed
an improved type of
Astrolabe (a saJilza)

21. Nizamul Mulk Tusi (vazir of Malik Shah Saljuqi)
In 1074-75 A.D established an observatory
at Rayy or Neshapur

22. Al-Tusi made the most significant work in developing the
model of planetary system of his time.
He wrote a major astronomical treatise called,
Al-Tadhkira Fi 'Ilm Al-Hay'a

23. Al Tusi made an observatory under the guidance of
Omar Khayyam where astronomical observations were made
Omer Khayyam
(1048—1123, Iran)
Calendar : Al-Tarikh Jalali.

24. Ibn al-Razaz al-Jazari (1136
Mathematician
Mechanical Engineer
Astronomer
– 1206)

25. Al-Jazari invented the largest
astronomical clock, "castle clock",
which is considered to be the first
programmable analog computer
Features
• Displayed the zodiac and the solar and
lunar orbits
• Another innovative feature of the clock
was a pointer which traveled across the
top of a gateway and caused automatic
doors to open every hour

26. Ulugh Beg (1394 - 1449)
Founder of a large
Islamic observatory in
Samarqand, honored on
this Soviet stamp
observatory in Samarqand (1428-1429)

27. Ibn Masud al-Kashi (1380 -1429 Iran)
Invented
“plate of conjuntions”
Conjunction means two celestial
bodies appear near one another
Planetary conjunction
in the sky

28. Ibn al-Shatir invented the astrolabe clock in
14th century Syria.