Ottoman Sundials

Roger BaileyNASS, St Louis, 2008

Ottoman SundialTopkapi 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 (1453-1481)

• Renovated in 1794 by Seyyid Abdullah

Ottoman SundialMissouri 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

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 (1368-1644)• Ottoman? Mehmet II (the Conqueror)

http://en.wikipedia.org/wiki/List_of_state_leaders_in_1480

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

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

Battle of Lepanto 1571

Ottoman navy defeated by Don Juan and combined fleet of Holy League

Mehmet II• Sultan 1453-1481• Emperor, warrior,

scholar• Built Istanbul:

Topkapi Palace• Converted Hagia

Sophia to a mosque

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

Hagia Sophia: IstanbulByzantine Cathedral: “Divine Wisdom” Roman Emperor Justinian 5371453’s Sultan’s Mosque, now museum

Hagia Sophia: Istanbul

Topkapi Palace, Istanbul

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

Topkapi Ottoman Sundial

Topkapi Palace Ottoman Sundial

Ezanic Hours

Asr

Italian

Babylonian

Polar Gnomon Support

Hour Lines:Angles

Hour Scale: Based on Noon as 6 o’clock. Ottoman Turk Numbers

Outer Scale:Polar

Sundial

Tan (Hour Angle) = Tan (time angle) x Sin (latitude)

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 sundialsReplica in Damascus Museum

Ezanic Hours At sunset, day ends 12 and starts at

0Vertical Peg Gnomon

Tip of shadowtells time

Date Lines:Shadow pathOn solstices and equinox

Summer 21 June

Winter 21 June

Ezanic Hours: Sunset 12 off scale to east (left) 24 in Italian Hours

11

11

12

1

10

2

3

4

5

Babylonian Hours: Sunrise 12 off scale to west(right). Mirror image

Moslem Prayer Times

Asr starts when shadow length is noon shadow + gnomon heightAsr ends when shadow length is noon shadow + twice gnomon height

Ibn al-Shatir Sundial

Kairouan, TunisiaGreat Mosque

http://astrotunisie.one-forum.net/culture-astronomique-f6/les-cadrans-solaires-en-tunisie-t31.htm

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

Kairouan Mosque Sundial

Veni CamiiIstanbul: New Mosque Yeni Camii

Vertical Declining Sundials

New Mosque Yeni Camii 2Local hours 20’

Polar Gnomon bent horizontal(Moslem style)

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

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 3Islamic sundialPrayer timesHours? 20’

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

Missouri Botanical Garden

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

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

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

Fer de Vries: ZW 2000A 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

http://www.de-zonnewijzerkring.nl/eng/index-vlakke-zonw.htm

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

Ottoman Sundial for Local Solar Time

Hours from Sunrise

1

212

103 4 6 8

1

Ezanic Sundial : SunriseNorth

South

West East

Sunrise 12 &0 off scale to West (left), 24 in Babylonian Hours

Babylonian Hours are the reverse of Italian

Peg Gnomon

Winter AM 2 hours after sunrise

Ezanic Sundial : Sunset

12

1

2

34

5

11

6 7 910

8

11

Date Lines:

Shadow path

On solstices and equinox

Summer 21 June

Winter 21 December

Equinox

North

South

West East

Ezanic Hours: Sunset 12 off scale to east (right) 24 in Italian Hours

Hours from previous Sunset

Peg Gnomon

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

1 112

12

105 83 7 94 6

12

11 1

WestEast

Equinox

Red: Italian SunsetBlue: Babylonian

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

DailyPrayer Times

Midnight

Midday

Sunrise Sunset

Daybreak Nightfall

Monastic

Prime

Matins

Triece

Sext

Nones

Vespers

Compline

zuhr

asr

maghrib

ishafajr

Moslem

duha

Moslem Prayer Times

Gnomon

Noon Zuhr

Defined by altitude of sun determined by shadow lengths

Zuhr = Noon + ¼ gnomon height

Asr = Noon + gnomon height to Noon + 2 gnomon heights

Asr

Moslem Prayer Timelines

Istanbul: Latitude 41º N Horizontal with Vertical Gnomon

Zon 2000

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

Full Size on E drawing (44" x 34")

8 9765

10

43

2

1

12

11

11

1 2 3

4

5

66

7

8

9 1 1 121 0

77

Qibla: N 47.2º EDirection to Mecca

Gnomon 15 cm Peg

Winter Solstice 21 December

Summer Solstice21 June

EastWest

NorthNoon

Gnomon 2Support

Gnomon 2 Polar Rod 38.6º

South

East West Line 12 Italian & Babylonian

63.22

76.20 cm30 inches

76.20 cm30 inches

31.62

30.00 26.35

12.52

38.87

Ottoman SundialMissouri Botanical GardensMBG 2: Description R3 4 Mar 2008Walking Shadow Designs

Western Hours based on 12 noon

Italian Hours based on 12 Sunset

Babylonian Hours based on 12 Sunrise

Moslem Afternoon Prayer Times

Zuhr: Noon Shadow+ 1/4 Gnomon Height

Asr 1: Noon Shadow + Gnomon Height

Asr 2: Noon Shadow + 2 x Gnomon Height

• This symbol represents the Mosque, Mihrab & Qibla• Great Circle Qibla St Louis to Mecca is N 47.2º E

Full Size on E drawing (44" x 34")

8 9765

10

43

2

1

12

11

11

1 2 3

4

5

66

7

8

9 1 1 121 0

77

Qibla: N 47.2º EDirection to Mecca

Gnomon 15 cm Peg

Winter Solstice 21 December

Summer Solstice21 June

EastWest

NorthNoon

Gnomon 2Support

Gnomon 2 Polar Rod 38.6º

South

East West Line 12 Italian & Babylonian

63.22

76.20 cm30 inches

76.20 cm30 inches

31.62

30.00 26.35

12.52

38.87

Ottoman SundialMissouri Botanical GardensMBG 2: Description R3 4 Mar 2008Walking Shadow Designs

Western Hours based on 12 noon

Italian Hours based on 12 Sunset

Babylonian Hours based on 12 Sunrise

Moslem Afternoon Prayer Times

Zuhr: Noon Shadow+ 1/4 Gnomon Height

Asr 1: Noon Shadow + Gnomon Height

Asr 2: Noon Shadow + 2 x Gnomon Height

Gnomons: Polar & Peg

1.36

2.00

5.66

4.93

4.28

3.72

3.24

2.82

2.45

3.00.80

1.23

Vertical Gnomon 5 cm highBronze

Gnomon SupportBronze

5.00

4.00

.81

.73

.71

.69

.79

.77

.75

1.00

1.23

2.00

1.50

2.00

4.17

38.6°

58.60

Each ring diameter is15%more than the ring above

Rings are elipses width = 85% height

42.50

12.50

1.00

.30 DIA

73.66 cm28"

15.00 cm6"

35.56Gnomon SupportRotated 90ºTo Show Rings

5.00

6.00

Marble Base for Sundial (28" x 28" x 6")

30.00

38.10

33.95

54.41

Ottoman SundialGnomon DetailsMBG 4 R4 7 Mar 2008Walking Shadow Designs

Full Size on D paper, 34" x 22"Dimensions in centimeters cm

Polar Gnomon 6mm (.25")Bronze Rod

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

1.36

2.00

5.66

4.93

4.28

3.72

3.24

2.82

2.45

3.00.80

1.23

Vertical Gnomon 5 cm highBronze

Gnomon SupportBronze

5.00

4.00

.81

.73

.71

.69

.79

.77

.75

1.00

1.23

2.00

1.50

2.00

4.17

38.6°

58.60

Each ring diameter is15%more than the ring above

Rings are elipses width = 85% height

42.50

12.50

1.00

.30 DIA

73.66 cm28"

15.00 cm6"

35.56Gnomon SupportRotated 90ºTo Show Rings

5.00

6.00

Marble Base for Sundial (28" x 28" x 6")

30.00

38.10

33.95

54.41

Ottoman SundialGnomon DetailsMBG 4 R4 7 Mar 2008Walking Shadow Designs

Full Size on D paper, 34" x 22"Dimensions in centimeters cm

Polar Gnomon 6mm (.25")Bronze Rod

Merge DXF FilesEnd of First DXF**VERTEX 8L_A 10 0.0000 20 -12.51930SEQEND 8L_A0ENDSEC0EOF

Start of Second DXF  0SECTION2ENTITIES0LINE 8L_$ 10 -2.5000 20 85.0000****

File Conversions1.Rename ZW *.dxf as *. Txt2. Edit as *.txt3. Save and rename *.txt as *.dxf4. Import into CAD5. Trim lines to design in CAD6. Print final as pdf to print full size at any copy shop

Construction: Abraham Molher 11 March – Marble

1 April – Carving 7 April – Gnomons

9 May – Installation

16 May -Dedication

Correction to Clock TimeEquation of Time + Longitude Correction

-20.00

-15.00

-10.00

-5.00

0.00

5.00

10.00

15.00

20.00

04/ Dec 07 02/ Feb 08 02/ Apr 08 01/ Jun 08 31/ Jul 08 29/ Sep 08 28/ Nov 08 27/ Jan 09

Date

Co

rre

cti

ion

to

Clo

ck

Tim

e (

Min

)

Equation of Time

+Longitude

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

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 -4:41– Longitude 25’15” -1:02

• Clock to Solar 10:25• Observed Error 8 min• Predicted Error 15 min

Sundial Orientation Error: 7.5ºMissouri Botantical Garden

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

0:00:00 2:24:00 4:48:00 7:12:00 9:36:00 12:00:00 14:24:00 16:48:00 19:12:00 21:36:00

Time

Err

or

(Min

)

Summer 23.44º

Dec 12º

Equinox 0º

Dec= -12º

Winter -23.44º

Sunrise SunsetNoon

Summer

Winter

8 9765

10

43

2

1

12

11

6

Full Size on E drawing (44" x 34") 28 inch square Marble Base

2

N

Ottoman SundialMissouri Botanical GardensMBG 7.5 Template RO-1 Aug 1 2008Walking Shadow Designs

7

5

4

11

3

112

111 0

9

8

7

6

5

8

Stone is off North axis by 7.5º East

Reorientation Design

• Dial oriented to polar axis

• Stone oriented to Garden axis, 7.5º east

• Outer dial scale oriented with stone

Reorientation Design

• Dial oriented to polar axis

• Stone oriented to Garden axis, 7.5º east

• Outer dial scale oriented with stone

Proud Artisans

• Abraham Mohler Sculptor

• Roger Bailey Designer

Ottoman SundialMissouri 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

Islamic Culture and ScienceAstronomy and Mathematics

• 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

•Astronomy•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

Library Hagia Sophia

One Book: Koran

The End

References and Photo Credits• Istanbul Topkapi Palace, Sundial of the Month, Dec 2005” Joel Robic

http://pagesperso-orange.fr/cadrans.solaires/cadrans/cadran-istanbul-topkapi.html • “Principle and Use of Ottoman Sundials” Atilla Bir http://muslimheritage.com/topics/default.cfm?ArticleID=942• “OSMANLILARDA GÜNEŞ SAATLERİ” Prof. Dr. Atilla Bir

www.akat.org/ast_tarihinden/osmanli_zamani/gunes_saati/• “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

http://www.de-zonnewijzerkring.nl/eng/index-vlakke-zonw.htm• “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• “Error Analysis of the Horizontal Sundial – IX Dial Rotation” T. J. Lauroesch and J. R. Edinger, Jr. , NASS Compendium 4-4 Dec

1997

• 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