ANCIENT CHINESE ASTRONOMY
• INHABITED WORLD CALLED “TIANXIA”
• AREAS OF ASTRONOMICAL INTEREST
– “LIFA” – CALENDRICAL METHODS –
MEASUREMENT AND MASTERY OF REGULAR
ASTRONOMICAL MOVEMENTS
– “TIANWEN” – CELESTIAL PATTERNS – STUDIES IN
WHICH ONE OBSERVED UNPREDICTABLE
ASTRONOMICAL PHENOMENA AND
INTERPRETING THE IMPORTANCE OF THESE
PHENOMENA TO HUMANS
ANCIENT CHINESE ASTRONOMY
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PRACTITIONERS OF BOTH LIFA AND TIANWEN WERE PERSONS OF IMPORTANCE – ON THE
EMPEROR’S STAFF
TIAN (HEAVEN) WAS IN IMPERSONAL ENTITY WHOSE WILL IT WAS THAT ORDER IN THE
WORLD SHOULD BE MAINTAINED. IF ORDER WAS DISRUPTED, FAMINE, PLAGUES AND
OTHER DISASTERS MIGHT OCCUR.
THE TIANWEN WERE THE PRACTIONERS WHO ADDRESSES SUCH ISSUES.
LIFA SPECIALISTS STUDIED REGULAR ASTRONOMICAL MOTIONS SO THE EMPEROR COULD
CONSTRUCT AN ALMANAC THAT DEMONSTRATED THE ORDER OF HIS RULE. STARTING WITH
EMPEROR WU OF THE HAN DYNESTY IN 104 BC THERE WERE 47 SUCH SYSTEMS GENERATED.
EVERY SYSTEM REQUIRED A LUNI-SOLAR CALENDAR (12 LUNAR MONTHS PER YEAR + AN
INTERCALARY MONTH AS NEEDED)
THE INTERCALARY MONTH WAS CALLED “RUN YUE”.
MONTHS BEGAN WITH NEW MOON
THE WINTER SOLSTICE WAS THE BASIC MARK POINT OF THE SEASONS.
THEY WERE ABLE TO PREDICT THE MOTIONS OF THE PLANETS AND THE OCCURRENCE OF
LUNAR ECLIPSES BUT NOT SOLAR ECLIPSES.
SOLAR ECLIPSES BELONGED TO THE DOMAIN OF THE TIANWEN
ANCIENT CHINESE ASTRONOMY
• LIFA SPECIALISTS USED NUMERICAL RATHER
THAN GEOMETRIC MATHEMATICS
• THE ACTIVITIES OF TIANWEN SPECIALISTS TRACE
BACK AS FAR AS THE 2ND MILLENIUM BC
• THEY WERE INTERESTED IN METEOR SHOWERS,
COMETS, SOLAR ECLIPSES, SUNSPOTS, NOVAE,
AURORAE, ETC.
• THEY HAD ACCESS TO SOPHISTICATED ARMILLARY
SHPERES AND KNEW THE HEAVENS AS WELL AS
ANY ANCIENT ASTRONOMERS UP TO THE TIME
OF TYCHO BRAHE
ANCIENT CHINESE COSMOLOGY
• THE INHABITED WORLD WAS A SMALL
REGION NEAR THE CENTER OF A FLAT EARTH
• IT WAS LOCATED ON A DIAMETRIC PLANE AT
THE CENTER OF A CELESTIAL SPHERE
• THE SPHERE ROTATED ON AN INCLINED AXIS
• CELESTIAL BODIES MOVED ON THE INNER
SURFACE OF THIS SPHERE
ANCIENT CHINESE ASTRONOMY
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CRAB SUPERNOVA
A NAKED EYE OBJECT
OCCURRED IN 1054 AD
OBSERVED BY TWO TIANWEN ASTRONOMERS
WHO ANNOUNCED TO THE EMPEROR THAT THIS
EVENT BODE GREAT THINGS FOR HIS RULE
• HE HAD THEM BEHEADED
• ALSO OBSERVED BY ARABIAN ASTRONOMERS
• NOT RECORDED IN EUROPEAN ANNALS
CRAB NEBULA
VISIBLE LIGHT
COMPOSITE PHOTO
ARABIC AND ISLAMIC ASTRONOMY
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AS ROMAN RULE DECLINED ARABIAN ASTRONOMY BECAME MORE IMPORTANT
ST. EPHREM FOUNDED A SCHOOL IN EDESSA IN MESOPOTAMIA CIRCA 350 AD.
THEY TRANSLATED MANY OF THE GREEK TEXTS INTO SYRIAC
LATER THE SCHOOL MOVED TO JUNDISHAPUR WHERE CHRISTIAN PHYSICIANS
HELPED THEM TRANSLATE GREEK MEDICAL TEXTS TO SYRIAC.
UPON DISCOVERING THE TREASURE OF OTHER GREEK MANUSCRIPTS HARUN ALRASHID (CALIPH IN 786) SENT AGENTS TO BUY GREEK MANUSCRIPTS.
CALIPH AL-MA’MUN ESTABLISHED THE “HOUSE OF WISDOM” IN BAGHDAD WHERE
THE CHRISTIAN HUNAYN IBN ISHAQ AL-IBADI HELPED TRANSLATE GREEK WORKS
INTO ARABIC AND SYRIAC
THE SPREAD OF ISLAM INSURED THAT A WIDE RANGE OF PEOPLES WOULD
UNDERSTAND THE TEXTS WRITTEN IN ARABIC.
MANY OF THESE WORKS WERE LATER TRANSLATED BACK INTO LATIN AND GREEK
AND, EVEN THOUGH THEY MAY HAVE SUFFERED DUE TO MULTIPLE
TRANSLATIONS, IN MANY CASES THESE ARE THE ONLY COPIES OF THE ORIGINAL
WORKS.
CHALLENGES OF ISLAM TO
ASTRONOMY
I. THE LUNAR CALENDAR
– MOHAMMED TAUGHT AGAINST INTERCALARY
MONTHS
– THIS MADE THE CALENDAR YEAR ABOUT 11 DAYS
SHORT OF THE SEASONAL YEAR
– EACH MONTH BEGAN WITH THE FIRST SIGHTING OF
THE WAXING CRESCENT MOON IN THE WESTERN SKY
SO NEIGHBORING TOWNS COULD RECKON THE
BEGINNING OF A MONTH DIFFERENTLY.
– RAMADAN, UNLIKE MANY OTHER RELIGIOUS
HOLIDAYS (LIKE EASTER), COULD OCCUR DURING ANY
SEASON
CHALLENGES OF ISLAM TO
ASTRONOMY
II. PRAYER TIMES ARE SET TO BE AT: SUNSET,
NIGHTFALL, DAYBREAK, MIDDAY AND AFTERNOON.
A. TIMES VARIED WITH LATITUDE AND LONGITUDE
B. MUWAQQITS (TIMEKEEPERS) WERE INSTITUTED
IN MOSQUES WHEN THE BASIC TRIGONOMETRIC
FUNCTIONS WERE DEVELOPED.
C. ASTRONOMY BECAME A NOBLE PROFESSION AND
THE QUALITY OF ASTRONOMICAL OBSERVATIONS
IMPROVED MARKEDLY.
D. ASTROLOGY WAS (AND IS) DETESTED BY ISLAM
CHALLENGES OF ISLAM TO
ASTRONOMY
III.
MOSQUES HAD TO BE ORIENTED TOWARD MECCA AND YOU
NEED TO FACE MECCA WHEN PRAYING (DO YOU ORIENT IT AS IF
TRAVELING ALONG A GREAT CIRCLE?)
A. EARLY SPANISH MOSQUES SIMPLY FACED SOUTH
B. “QIBLA”, THE SACRED ORIENTATION, WAS OCCASIONALLY
ASSUMED TO BE THE DIRECTION TOWARD WHICH PILGRIMS
HEADED FOR MECCA STARTED
C. WHEN SPHERICAL GEOMETRY WAS PERFECTED TABLES WERE
GENERATED TO DICTATE WHAT DIRECTION A MOSQUE SHOULD
BE ORIENTED GIVEN ITS LATITUDE AND LONGITUDE.
DEVELOPMENT OF ISLAMIC
ASTRONOMY
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PTOLEMY’S ALMAGEST GAVE THEM A MODEL TO EMULATE
BETTER OBSERVATIONS WERE NEEDED
OBSERVER’S WERE LARGELY ASTROLOGERS WHO WERE CONDEMNED BY ISLAM AS
“FORTUNE TELLERS”.
HOWEVER THEIR OBSERVATIONS WERE VALUED AND USED.
GOOD OBSERVATORIES WERE LARGE AND NEEDED FIXED FACILITIES (THE START OF WHAT
WE CALL “OBSERVATORY”)
SEVERAL OBSERVATORIES WERE BUILT BY RULERS OR RICH PATRONS BUT FAILED WHEN THE
RELIGIOUS LEADERS HAD THEM KILLED.
– VIZIER OF THE FATAMID CALIPH ORDERED CONSTRUCTION OF AN OBSERVATORY IN
1120. HE WAS KILLED BUT THE CONSTRUCTION CONTINUED UNTIL 1125 WHEN THE
NEW VIZIER WAS KILLED FOR “COMMUNICATING WITH SATURN” AND THE
OBSERVATORY WAS DEMOLISHED.
– AN OBSERVATORY WAS BUILT IN ISTAMBUL IN 1575 (CONTEMPORARY WITH TYCHO).
THE ASTRONOMER TAQI AL-DIN OBSERVED A BRIGHT COMET IN 1577 WHICH HE
INTERPRETED AS A POSITIVE SIGN TO THE SULTAN. HOWEVER MISFORTUNE
FOLLOWED. IN 1580 THE SULTAN HAD THE OBSERVATORY DEMOLISHED AS THE URGING
OF THE RELIGIOUS LEADERS.
DEVELOPMENT OF ISLAMIC
ASTRONOMY
1. TWO SUCCESSFUL OBSERVATORIES
– MARAGHA – NORTHERN IRAN
• BUILT BY HULAGU, MONGOL RULER OF PERSIA, WHO LIKED
ASTROLOGY
• CHIEF ASTRONOMER WAS NASIR AL-DIN AL-TUSI
• CONSTRUCTION BEGAN IN 1259
• GENERATED TABLES CALLED “ZIJ”
• INSTRUMENTS
– MURAL QUADRANT (MEASURED ALTITUDES) – 14 FOOT RADIUS
– ARMILLARY SPHERE (FIVE FOOT RADIUS)
• THE OBSERVATORY CLOSED WHEN AL-TUSI DIED IN 1274
DEVELOPMENT OF ISLAMIC
ASTRONOMY
2.
IN 1447 AN OBSERVATORY WAS BUILT AT SAMARKAND IN CENTRAL ASIA
A. BUILT BY ULUGH BEG, GRANDSON OF TAMARLANE IN 1420.
B. PRIMARY INSTRUMENT WAS A TRANSIT INSTRUMENT IN THE FORM OF A
SEXTANT
C. IT WAS OVER 130 FEET IN RADIUS
D. DEVELOPED A CATALOG OF OVER 1,000 STARS
E. THESE UNIQUE OBSERVATIONS ARE CONSIDERED TO BE THE ONE IMPORTANT
STAR CATALOG OF THE MIDDLE AGES.
F. IN 1449 ULUGH BEG WAS MURDERED AND THE OBSERVATORY WAS CLOSED.
ARABIC PLANETARY ASTRONOMY
• IN 770 A ZIJ (ASTRONOMICAL TABLE) WAS COMPOSED IN BAGHDAD
BY AL-KHWARIZMI.
• MANY OF THE DATA DERIVED FROM DOCUMENTS BROUGHT THERE
FROM INDIA
• ANOTHER ZIJ WAS GENERATED IN THE EARLY 900’S AD BY
MUHAMMAD AL-BATTANI. IT WAS TRANSLATED INTO LATIN AND
USED EXTENSIVELY BY COPERNICUS.
• ABD AL-RAHMAN AL-SUFI, A TENTH-CENTURY ASTRONOMER,
WROTE, BOOK ON THE CONSTELLATION OF FIXED STARS.
HOWEVER HIS MEASUREMENTS WERE LARGELY INACCURATE EVEN
THOUGH THEY HAD THE ASTROLABE. THEY WERE MORE
INTERESTED IN THE PLANETS THAN THE STARS.
• AL-SUFI AND THABIT IBN QURRA HAD SHUKUK (DOUBTS)
CONCERNING PTOLEMY’S MODEL.
• PTOLEMEY’S EQUANT WAS HEAVILY CRITICIZED.
ARABIC PLANETARY ASTRONOMY
• IN THE 12TH CENTURY, MUHAMMAD IBN RUSHD (KNOWN AS “THE
COMMENTATOR”) REJECTED PTOLEMY’S MODELS AND PROPOSED
CONCENTRIC SPHERES.
• HIS IDEAS WERE GROSSLY INACCURATE
• ECCENTRIC SPHERES WERE LESS OBJECTIONABLE THAN EQUANTS
BUT STILL REGARDED AS UNSATISFACTORY
• IBN AL-SHATIR, MUWAQQIT OF THE UMAYYAD MOSQUE IN
DAMASCUS PROPOSED AN EPICYCLE SYSTEM WITH THE EARTH AT
THE TRUE CENTER.
• HE ADDED A SECOND EPICYCLE WHICH MOVED WESTWARD
(CLOCKWISE) ON THE PRIMARY EPICYCLE WHICH MOVED
EASTWARD AT THE RATE OF THE “MEAN” MOON ON THE
DEFERENT. THE MOON MOVED ON THE EASTWARD ON THE
SECOND EPICYCLE.
AL-SHATIR’S MODEL
THE ASTROLABE
• DEVELOPMENT BEGAN AS EARLY AS 150 BC
• PERFECTED BY ISLAMIC ASTRONOMERS BETWEEN 800 AND 1200 AD
• USES
– DETERMINE CURRENT TIME BASED ON THE ELEVATION (ALTITUDE) OF A STAR
– PREDICT THE TIME OF A FUTURE ASTRONOMICAL EVENT, SUCH AS SUNRISE,
MOON RISE, ETC.
• FOUR KINDS
– PLANISPHERIC
• MOST WIDELY USED
• A PROJECTION OF THE SPHERICAL ASTROLABE ONTO A PLANE
– LINEAR
– SPHERICAL
– MARINER’S (A PRECURSOR TO THE MODERN DAY SEXTANT)
ASTROLABE
ISLAMIC SPHERICAL ASTROLABE
MARINER’S ASTROLADE