1. Roger Bailey NASS, St Louis, 2008
Ottoman Sundials
Roger Bailey
NASS, St Louis, 2008

2. Ottoman Sundial Topkapi Palace, Istanbul
Sundial in Third Garden of Topkapi Palace, near Library of Ahmet III.
Designed by Suleyman, the first secretary of the Treasury in the reign of Memhet II, the Conqueror ( )
Renovated in 1794 by Seyyid Abdullah

3. Ottoman Sundial Missouri Botanical Garden
Topkapi Dial design for Ottoman Garden at Missouri Botanical Garden, St Louis
Paul Brockman: Project Coordinator
E.L. Bakewell Jr: Sponsor
Fazil Sutcu: Architect
Abraham Mohler: Sculptor
Roger Bailey: Designer
From Istanbul to St Louis, an interesting project. To understand why we need a historical perspective. Lets go back to 1480 when the original dial was constructed. What was happening in the world at that time? Who were the superpowers, nations that influenced world politics beyond their bordersIn those days what

4. 15th Century Superpowers
Holy Roman Empire? Fredrick III,
Spain? Isabella & Ferdinand
England? 1485 Henry VII, War of Roses
France? Louis XI (the Prudent)
Florence?, Medici, Papal States? Borgia
China? Ming Dynasty ( )
Ottoman? Mehmet II (the Conqueror)
From Istanbul to St Louis, an interesting project. To understand why we need a historical perspective. Lets go back to 1480 when the original dial was constructed. What was happening in the world at that time? Who were the superpowers, nations that influenced world politics beyond their borders in those days. Europe was in turmoil with no dominant or Imperial superpower. The nations that we know today did not exist but were waring fiefdoms whose allegiances depended more on royal marriages than geography, culture or language. China had begun its period of isolation following the remarkable voyages of America was yet to be officially discovered. The Ottomans in Turkey we the force to be reckoned with.

5. Mehmet the Conquorer
Constantinople, centre of the world, where East meets West
Ottoman Turks took
Constantinople in 1453
Ended Byzantine Empire started by Constantine in 330
Expanded Ottoman Empire in Middle East and Eastern Europe
The Ottomans, originally Turkish raiders from the steepes of Central Asia were expanding their empire. The key conquest by Mehmet II in 1453 took Constantinople and finished the Byzantine Empire, the eastern remnant of the Roman empire. This made Constantinople the center of the expanding Ottoman Empire.

6. Constantinople as at the divide between east and west, Europe and Asia
Constantinople as at the divide between east and west, Europe and Asia. The Byzantines were the last remnant in the east of the Roman Empire and Christianity, Islam was the religion of the East and expanding its influence from the days of the prophet Mohamed in Arabia in the 6th century (558)

7. Battle of Walachia 1462
Count Dracula of Transylvania, Vlad III (the Impaler), rebelled and fought back in Walachia in 1462
Impaled 20,000 Turkish prisoners
Vlad captured and executed but stopped the Ottoman advance across Europe
There was resistance to the westward expansion History records that Count Dracula from Transilvania stopped the Ottoman forces in Walachia ( Bulgaria). Dracula was also known as Vlad the Impailer for his cruel execution technique. I am not making this up. These were cruel and brutal time that we in the west know little about.

8. Battle of Lepanto 1571
Ottoman navy defeated by Don Juan and combined fleet of Holy League
At Lepanto, on Oct. 7, 1571, the Ottoman navel fleet battled between the Christians in the strait between the gulfs of Pátrai and Corinth, off Lepanto (Návpaktos), Greece. The fleet of the Holy League commanded by John of Austria (d. 1578) opposed the Ottoman fleet under Uluç Ali Pasha. The allied fleet (about 200 galleys, not counting smaller ships) consisted mainly of Spanish, Venetian, and papal ships and of vessels sent by a number of Italian states. It carried approximately 30,000 fighting men and was about evenly matched with the Ottoman fleet. The battle ended with the virtual destruction of the Ottoman navy (except 40 galleys, with which Uluç Ali escaped). Approximately 15,000 Turks were slain or captured, some 10,000 Christian galley slaves were liberated, and much booty was taken. The victors, however, lost over 7,000 men. Among the allied wounded was Cervantes, who lost the use of his left arm. Lepanto was the first major Ottoman defeat by the Christian powers, and it ended the myth of Ottoman naval invincibility. It did not, however, affect Ottoman supremacy on the land, and a new Turkish fleet was speedily built by Sokollu, grand vizier of Selim II. Nevertheless, the battle was decisive in the sense that an Ottoman victory probably would have made the Ottoman Empire supreme in the Mediterranean.

9. Mehmet II Sultan 1453-1481 Emperor, warrior, scholar
Built Istanbul: Topkapi Palace
Converted Hagia Sophia to a mosque
Meanwhile back in Constantinople, now known as Istanbul, the Sultan was establishing his government and the Ottoman culture

10. Topkapi Ottoman Sundial
Drawn by Suleyman Bey, Secretary of the Treasury for Sultan Mehmet II
Similar to sundials at Damascus & Kairouan, Tunisia
Two gnomons, four time systems
Represents science, culture, religion, and empire

11. Hagia Sophia: Istanbul
Byzantine Cathedral: “Divine Wisdom”
Roman Emperor Justinian 537
1453’s Sultan’s Mosque, now museum

12. Hagia Sophia: Istanbul

13. Topkapi Palace, Istanbul
Build by Mehmet II on ruins of Byzantine palaces
Palace, harem, government center, gardens
Ottoman sundial in Third Garden

14. Topkapi Ottoman Sundial

15. Topkapi Palace Ottoman Sundial
This is what the veiled women were viewing. A strange pattern of lines and Arabic writing. What does it mean? The lines are the hour lines for two different sundials and show four different systems of measuring time.

16. Ezanic Hours
The called the hours show on the inner dial Ezanic hours. My Italian collegue Gianni Ferrari that In Turkish language ezan or azan is the call to prayer. This is from Arabic, Adhan, the Islamic call for the prayers that have to be recited in Islamic lands five times each day. ezani = pertaining to the azan and ezani saat is the hour as reckoned from sunset. So this sundial is based on the day starting and ending at sunset and regulates the time for prayers.

17. Italian
Babylonian
Asr

18. Outer Scale: Polar Sundial
Hour Lines:Angles
Tan (Hour Angle) = Tan (time angle) x Sin (latitude)
The outer scale is what we would recognize as a sundial. The thin rod or wire shows by its angle the time of day based on noon being the reference point. The ottoman Turk numbers show noon was 6 o’clock. This is noon as we know it, mid-day when the sun is highest in the sky and due south.
Polar Gnomon Support
Hour Scale: Based on Noon as 6 o’clock. Ottoman Turk Numbers

19. Ibn al-Shatir ‘s Sundial Damascus Umayyad Mosque
Horizontal sundial on north Minaret until ~1900
By Ibn al-Shatir in 1371
Astronomer, mathematician, timekeeper (muwaqqits)
Planetary theory like Copernicus
First polar sundials including Compass Compendium
Showed time relative to sunset, sunrise, noon and afternoon
Model for Ottoman sundials
There are other sundials with similar lines and time systems. The first was the dial designed by Ibn al-Shat
Replica in Damascus Museum

20. Ezanic Hours At sunset, day ends 12 and starts at 0
Vertical Peg Gnomon
Summer 21 June 11
Date Lines:
Shadow path
On solstices and equinox 12 1 2
Tip of shadow
tells time 10 3
Lets isolate the butterfly shape in the middle that shows enzanic hours. These are referenced to the length of the shadow from the small vertical peg gnomon. The tip of the shadow tells the time. 5
Winter 21 June 4 11
Ezanic Hours: Sunset 12 off scale to east (left) 24 in Italian Hours
Babylonian Hours: Sunrise 12 off scale to west(right). Mirror image

21. Moslem Prayer Times
Prayer times based on the length of the shadow are also shown by this curved line. This is for the start of the important afternoon prayer “Asr”. Other dials show more prayer times.
Asr starts when shadow length is noon shadow + gnomon height
Asr ends when shadow length is noon shadow + twice gnomon height

22. Ibn al-Shatir Sundial

23. Kairouan, Tunisia Great Mosque

24. Kairouan, Tunisia Great Mosque
Sundial designed in 1842 (1258 H) by Almed Essoussi
Four peg gnomons
Inspired by Ibn al-Shatir dial in Damascus and Topkapi dial

25. Kairouan Mosque Sundial

26. Istanbul: New Mosque Yeni Camii
Veni Camii

27. Vertical Declining Sundials

28. New Mosque Yeni Camii 2 Local hours 20’ Polar Gnomon bent horizontal
(Moslem style)

29. New Mosque “Yeni Camii” 1 Local hours 20’ Ezanic hours Asr 1 & 2 Zhur?
Declination

30. New Mosque Yeni Camii 3 Islamic sundial Prayer times Hours? 20’
Overlay confirms declination lines, equinoctial and Asr Prayer line (N + G).
Zuhr Prayer line and parallel curved time lines are different
New Mosque
Yeni Camii 3
Islamic sundial
Prayer times
Hours? 20’

31. Why? Ottoman Sundials Complex and difficult to read but impressive
Four time systems:
Time systems from east and west
Religious and secular time
Call to prayer? Tell time? Perhaps
Understand and explain our universe?
Teach & demonstrate scientific prowess
Demonstrate the scope of the Empire

32. Missouri Botanical Garden

33. Missouri Botanical Garden
St Louis, Missouri
Ottoman Garden
Same Latitude as Istanbul
Exotic tulips
Water features
Ottoman Sundial
NASS Conference
Fred Sawyer NASS
Don Snyder NASS
Mike Olsen MBG

34. Ottoman Sundial
Topkapi Dial design for Ottoman Garden at Missouri Botanical Gardens, St Louis
Paul Brockman: Project Coordinator
Fazil Sutcu: Architect
Abraham Mohler: Sculptor
E.L. Bakewell Jr:Sponsor
Roger Bailey: Designer
From Istanbul to St Louis, an interesting project. To understand why we need a historical perspective. Lets go back to 1480 when the original dial was constructed. What was happening in the world at that time? Who were the superpowers, nations that influenced world politics beyond their bordersIn those days what

36. Differences: Topkapi and Missouri
Goal: Comprehension not confusion
Noon is 12 not 6 on polar dial
Arabic not Ottoman numbers
Fewer Lines
Time division: 5’ 15’ 30’ not 1’ 4’ 20’
Hours & Half hours (30 min) , not 20 minutes
Prefered view: from South
Latitude 41 vs 38.6

37. Fer de Vries: ZW 2000 A UNIFORM METHOD TO COMPUTE FLAT SUNDIALS
Principle: Convert the sun's position into coordinates for a shadow point on the dial's face
Solve for Altitude and Azimuth knowing Latitude for various times, Declinations, sundial types and orientations
Project the shadow of a point, the tip of a perpendicular gnomon onto the plane of the dial
Draw the timelines required
Clip drawing or export as a DXF file
Design the sundial, based on the timelines timelines

38. Polar Sundial Design
Outer dial with the polar gnomon is a simple standard Western design
Create the lines at the correct angles for the location using specific sundial design software “ZW 2000” by Fer de Vries
Bring the lines into a CAD program “Delta CAD” to trim and fit to design

39. Ezanic Sundial : Sunrise
North
South
West
East
Hours from Sunrise 1 2 12 10 3 4 6 8
Babylonian Hours are the reverse of Italian
Peg Gnomon
Winter AM 2 hours after sunrise
Sunrise 12 &0 off scale to West (left), 24 in Babylonian Hours

40. Ezanic Sundial : Sunset
North
South
West
East 12 1 2 3 4 5 11 6 7 9 10 8
Date Lines:
Shadow path
On solstices and equinox
Summer 21 June
Winter 21 December
Equinox
Peg Gnomon
Ezanic Hours: Sunset 12 off scale to east (right) 24 in Italian Hours
Hours from previous Sunset

41. Ezanic Timelines Simplified
Timelines seem confusing but are quite simple
Go back to the Bible: Third, Sixth, Ninth Hour etc.
Look at the Equinox, 12 hour days, mid-day is 6
All the hours are the same, crossing on the Equinox
East
West 1
Equinox 2 3 4 5 6 7 8 9 10 11 12 12
Red: Italian Sunset
Blue: Babylonian 1 11

42. Moslem Prayer Hours
For devout Moslems, there are five prayer times, all determined by the altitude of the sun
Fajr (morning): twilight to dawn
Zuhr (noon): Shadow length: noon + ¼ gnomon height
Asr (mid pm): Shadow length: noon + gnomon height to noon + 2 gnomon heights
Maghrib (sunset): sundown to end of twilight
Ish (night): twilight to dawn
Zuhr and Asr are (were) set by shadow lengths
Horizontal sundials with perpendicular gnomons

43. Monastic Moslem Daily Prayer Times Prime Matins Triece Sext Nones
Vespers
Compline
zuhr
asr
maghrib
isha
fajr
Moslem
duha
Midnight
Midday
Sunrise
Sunset
Daybreak
Nightfall
Daily Prayer Times

44. Moslem Prayer Times
Noon
Defined by altitude of sun determined by shadow lengths
Zuhr = Noon + ¼ gnomon height
Asr = Noon + gnomon height to Noon + 2 gnomon heights
Zuhr
Asr
Gnomon

45. Moslem Prayer Timelines
Zon 2000
Istanbul: Latitude 41º N
Horizontal with Vertical Gnomon

46. Qibla: Direction to Pray
Moslems pray towards Mecca, generally East
The direction is as important as the time
Mihrab (niche), in the Mosque is oriented to Mecca
Ottoman sundials often show the Qibla direction
This symbol represents the Mosque, Mihrab & Qibla
Great Circle Qibla St Louis to Mecca is N 47.2º E

48. Gnomons: Polar & Peg

49. Two Gnomon Problem
ZX 2000 does all the required timelines but for one gnomon height
Polar gnomon is 10 cm at origin, peg gnomon is 5 cm
Do two designs and merge DXF files

50. Merge DXF Files File Conversions 1.Rename ZW *.dxf as *. Txt
End of First DXF *
VERTEX 8
L_A 10
0.0000 20
SEQEND
ENDSEC
EOF
Start of Second DXF
SECTION 2
ENTITIES
LINE 8
L_$ 10 20 *
File Conversions
1.Rename ZW *.dxf as *. Txt
2. Edit as *.txt
3. Save and rename
*.txt as *.dxf
4. Import into CAD
5. Trim lines to design in CAD
6. Print final as pdf to print full size at any copy shop

52. Construction: Abraham Molher 11 March – Marble
1 April – Carving
7 April – Gnomons
9 May – Installation
16 May -Dedication

53. People think sundials are wrong. They are not
People think sundials are wrong. They are not. Clocks need to be corrected to the true local solar time as used before the railroads
Sundials tell true local solar time based on noon being the time when the sun is due south and at it’s highest elevation
Daylight savings is the biggest correction, 1 hour less than standard time
Clocks show averaged time for the center of their time zone. There is a correction for longitude, 4 min/degree
The correction at St Louis (90º25’15”) is only 1’02”
Clocks need to be corrected due real changes in the length of the day caused by the tilt and elliptical orbit of the earth
This correction is called the Equation of Time
The Equation of Time varies up to +/- 15 min through the year

54. Orientation Error!
After careful design, engraving, construction and alignment with the sun, the dial was arbitrarily reoriented
It “looks better lined up with the sidewalk”, ~ 9º off North
Errors are significant:
14 to 37 minutes
Worst when shadows are long
Winter, early AM and late PM
Error obvious from date lines

55. Orientation Error Check
Dial Reads 10:17 Solar
Picture taken 11:31 CDT, 5 July by Don Snyder
Corrections to clock
Daylight savings -1:00:00
Equation of Time :41
Longitude 25’15” :02
Clock to Solar 10:25
Observed Error 8 min
Predicted Error 15 min

57. Reorientation Design Dial oriented to polar axis
Stone oriented to Garden axis, 7.5º east
Outer dial scale oriented with stone

58. Reorientation Design Dial oriented to polar axis
Stone oriented to Garden axis, 7.5º east
Outer dial scale oriented with stone

59. Walking Shadow Designs
Proud Artisans
Abraham Mohler Sculptor
Roger Bailey Designer
Walking Shadow Designs

60. Ottoman Sundial Missouri Botanical Garden
Sundial is unique and significant
Only Islamic dial in public use in America
Only dial with Italian and Babylonian hours
Only dial with prayer times or Qibla
Shows what western civilization gained from the peak of Islamic science and culture
Appropriate for the Ottoman Gardens
There are some small Islamic dials in museums, gallaries and private collections

61. Islamic Culture and Science Astronomy and Mathematics
Arabic names for stars
Babylonian Deg:Min:Sec
Greek astronomy
Celestial Sphere
Astrolabe and sundials
Mathematics
Zero and Arabic numbers
Greek geometry
Algebra, algorithm
Spherical trigonometry
Dark Ages in Europe
Built on the best of East and West
Reintroduced texts and knowledge of Greeks and Romans
Ptolemy’s “Almagest”
Focus: Marking time
Calendar, lunar month
Prayer times
Direction to Mecca

62. The End Library Hagia Sophia One Book: Koran
Islam peaked with the Ottomans 500 years ago. Why?
Narrow science focus: timekeeping. One book: Koran
Warfare, repression, militancy, terrorism
Poor Government: Decadence and corruption
Religious fundamentalism, theocracy
Population and Poverty
Loss of arable land: overgrazing, erosion, exhaustion
Climate change? Deserts? Cause or Effect?
Back to the Middle Ages:
No Enlightenment, Reformation or Revolutions
One Book: Koran

63. References and Photo Credits
Istanbul Topkapi Palace, Sundial of the Month, Dec 2005” Joel Robic
“Principle and Use of Ottoman Sundials” Atilla Bir
“OSMANLILARDA GÜNEŞ SAATLERİ” Prof. Dr. Atilla Bir
“Sundials in Medieval Islamic Science and Civilization” Len Berggren, NASS, 8-2 June 2001
“Astronomy in the Service of Islam”, David A. King, Variorum 1983.
“In Synchrony with the Heavens” V1 “The Call of the Muezzin” D. A. King, Brill 2001
“A Uniform Method to Compute Flat Sundials” Fer de Vries: ZW 2000
“Error Analysis of the Horizontal Sundial – IX Dial Rotation” T. J. Lauroesch and J. R. Edinger, Jr. , NASS Compendium 4-4 Dec 1997
Les cadrans solaires de monde de l’Islam (Sundials in the Islamic World), Chapter X, Les cadrans solaires, histoire, théorie,practique” René Rohr, Oberlin, 1986 (This section is In European editions not North American editions in English, U o f T 1970 or Dover 1996)
The Meridian of Ibn Al Shatir –Umayyad Mosque in Damascus” Gianni Ferrari, unpublished personal communication
Slide 1: Atilla Bir “Principle and Use of Ottoman Sundials”
Slide 2,13,14,16: Alain Ferreira, Joel Robic, “Istanbul Topkapi Palace”
Slide 3,34,35, 51,52, 54, 56: Don Snyder
Slide 32: Ian Adams, Missouri Botanical Garden,
Slide 33, 57: Laila Wessel, Missouri Botanical Garden