MEDIEVAL LATIN ASTRONOMY

1. MEDIEVAL LATIN ASTRONOMY • “MIDDLE AGES” – TIME FROM THE FALL OF ROME IN 476 UNTIL THE FALL OF CONSTANTINOPLE IN 1453 • EVEN THOUGH ROME RULED AFTER IT CONQUERED GREECE IN THE 2ND CENTURY BC THE LANGUAGE OF SCHOLARSHIP WAS GREEK. • IN THE EARLY 500’S AD ANICIUS MANILIUS SEVERINUS BOETHIUS SET OUT TO TRANSLATE ALL OF THE ANCIENT GREEK WORKS INTO LATIN. • BEFORE ACCOMPLISHING MUCH HE WAS EXECUTED • BOETHIUS WORKS CODIFIED WHAT WE NOW CALL THE QUADRIVIUM: • ARITHMETIC (THEORY OF DISCRETE QUANTITIES) • HARMONY (THEORY OF NATURE) • GEOMETRY (THEORY OF CONTINUOUS QUANTITIES) • ASTRONOMY

2. MEDIEVAL LATIN ASTRONOMY • MARTIANUS CAPELLA OF CARTHAGE WROTE AN ALLEGORY OF HEAVENLY MARRIAGE IN THE 5TH CENTURY AD • IN IT HE DESCRIBED A SYSTEM SIMILAR TO THAT OF HERACLIDES (AND FORESHADOWING TYCHO’S SYSTEM) IN WHICH MERCURY AND VENUS CIRCLED THE SUN AND THE SUN, IN TURN, CIRCLED THE EARTH.

3. MEDIEVAL LATIN ASTRONOMY • AMBROSIUS THEODOSIUS MACROBIUS (5TH CENTURY AD) ENUNCIATED A COSMOLOGY DRAWN FROM PLATO AND THE PYTHAGOREANS: • SPHERICAL EARTH • CENTER OF THE UNIVERSE • ENCIRCLED BY SEVEN PLANETARY SPHERES • THEY WERE ENCIRCLED BY THE STARRY SPHERE WHICH ROTATED DAILY FROM EAST TO WEST DRAGGING THE PLANETARY SPHERES ALONG. • EACH PLANETARY SPHERE HAD ITS OWN MOTION • THE EARTH WAS DIVIDED BY OCEANS INTO FOUR QUARTERS • THE SIZE OF THE EARTH WAS THAT DETERMINED BY ERATOSTHENES

4. MEDIEVAL LATIN ASTRONOMY • A RELIABLE CALENDAR WAS NEEDED IN CHRISTENDOM, AS IN ISLAM, TO SET FESTIVAL TIMES • EASTER WAS DETERMINED TO OCCUR ON: • FIRST SUNDAY FOLLOWING THE • PASCHAL (DERIVED FROM THE WORD “PASSOVER”) FULL MOON (ACTUALLY 14TH DAY OF THE MOON) FOLLOWING - (DETERMINED USING METONIC CYCLE) THE • VERNAL EQUINOX • TIME OF DAY WAS IMPORTANT TO CERTAIN PRAYER TIMES AND VESPERS • DETERMINED BY: • LOCATION OF THE STARS • WATER CLOCKS • RHYTHMIC CHANTING

5. MEDIEVAL LATIN ASTRONOMY • ASTRONOMY REVIVED IN THE WEST WHEN CONTACT WITH ISLAMIC ASTRONOMERS WAS MADE THROUGH SPAIN IN THE 10TH CENTURY. • GERBERT OF AURILLAC (LATER POPE SYLVESTER II) BROUGHT KNOWLEDGE OF THE ASTROLABE FROM SPAIN TO ROME IN 1025 • ASTROLOGY BECAME IMPORTANT DURING THE BLACK PLAGUE (BLACK DEATH) OF 1348-1350 • ARISTOTLE’S ANALOGY OF THE HEAVENS AND THE HUMAN BODY (SEE PANEL TO THE RIGHT) PROMOTED MEASUREMENTS OF THE POSITIONS OF THE PLANETS.

6. MEDIEVAL LATIN ASTRONOMY • WHEN TOLEDO FELL IN 1085 MANY OF THE EARLIER ISLAMIC WORKS BECAME AVAILABLE TO THOSE IN THE WEST • GERARD OF CREMONA WENT TO SPAIN AND TRANSLATED MORE THAT 70 VOLUMES INTO LATIN • THEY COULD NOW PREDICT THE POSITIONS OF THE PLANETS • HOWEVER, THEORIES OF THE MOTIONS SET DOWN IN THE ALMAGEST REMAINED A MYSTERY TO THEM. • PARIS BECAME A CENTER OF LEARNING IN THE 13TH CENTURY. • THE STUDY OF ARTS AND SCIENCE WAS ELEVATED TO THAT OF THEOLOGY. • THOMAS AQUINAS ADDRESSED THE PROBLEMS THAT AROSE BY INTRODUCING “PAGAN” IDEAS INTO THEIR CURRICULUM. IN FACT ARISTOTILEAN IDEAS WERE ELEVATED TO THAT OF REVELATION. • THE ALMAGEST REMAINED TOO DIFFICULT FOR MOST STUDENTS.

7. MEDIEVAL LATIN ASTRONOMY • PARISIAN SCHOLARS ACKNOWLEDGED THAT PRECESSION OCCURRED • THEY ALSO (ERRONEOUSLY) THOUGHT THAT THERE WAS A VARIATION IN PRECESSION WHICH THEY LABELED “TREPIDATION”. • THEY WERE PARTICULARLY INTERESTED IN CORRELATING THE ARISTOTILEAN PARTS OF THE UNIVERSE WITH THOSE REFERRED TO IN THE BOOK OF GENESIS. • THE FIRST SEVEN SPHERES WERE THOSE OF THE PLANETS • THE EIGHTH SPHERE WAS THAT OF THE “FIRMAMENT”, WHERE THE FIXED STARS RESIDED AND IN WHICH PRECESSION OCCURRED. • GENESIS’ “WATERS ABOVE THE FIRMAMENT” REFERRED TO THE NINTH (OR NINTH AND TENTH) SPHERE. IT WAS CRYSTALLINE AND WAS WHERE “TREPIDATION” WAS THOUGHT TO OCCUR. • THE ELEVENTH SPHERE WAS MOTIONLESS. IT REFERRED TO HEAVEN, THE ABODE OF GOD.

8. MEDIEVAL LATIN ASTRONOMY • IN ABOUT 1230 JOHN OF HOLYWOOD (SACROBOSCO) WROTE THREE NEW TEXTBOOKS RELATED TO TIME KEEPING AND ASTRONOMY. • HIS SPHERE WAS ADOPTED AS A TEXT BUT WAS MOSTLY UNSATISFACTORY IN ITS TREATMENTS • AN ANONYMOUS TEXT THEORY OF THE PLANETS REPLACED IT. • IT WAS, IN TURN, REPLACED BY BETTER WORKS. • THE LEVEL OF MEDIEVAL ASTRONOMY PROGRESSED SLOWLY.

9. MEDIEVAL LATIN ASTRONOMY • IN THE 13TH CENTURY KING ALFONSO X OF CASTILE PUBLISHED A NEW SET OF TABLES OF PLANETARY MOTION • CALLED THE “ALPHONSINE TABLES” • THEY REPLACED THE OLD “TOLEDAN TABLES” INHERITED FROM THE ISLAMIC ASTRONOMERS • NEW INSTRUMENTS LIKE THE ASTROLABE APPEARED AND MASSIVE OLD OBSERVATORIES WERE NO LONGER NECESSARY.

10. MEDIEVAL LATIN ASTRONOMY THE OLD QUADRANT, USED TO MEASURE ALTITUDES THE NEW QUADRANT/ASTROLABE, INTRODUCED BY “PROFATIUS THE JEW”, JACOB BEN MAHIR

11. MEDIEVAL LATIN ASTRONOMY • THE CROSS STAFF • INTRODUCED BY LEVI BEN GERSON • MEASURED ANGLE BETWEEN TWO OBJECTS • USED TO DETERMINE A MARINER’S LATITUDE • MEASURED ALTITUDE OF SUN AT NOON • POLARIS NOT ADEQUATE IN 1500 AS IT WAS 3 DEGREES FROM THE POLE THEN

12. MEDIEVAL LATIN ASTRONOMY A NOCTURNAL – USED TO DETERMINE THE TIME AT NIGHT A NOCTURLABE – USED TO DETERMINE TIME AT NIGHT AND TO TIME THE TIDES

13. MEDIEVAL LATIN ASTRONOMYTIME KEEPING ASTRONOMICAL CLOCK OF RICHARD OF WALLINGFORD, ABBOT OF ST ALBANS, EARLY 14TH CENTURY ASTRARIUM – INVENTED BY GIOVANI DE’ DONDIIN 1364 , LIVED IN PADUA

14. PREVIOUSLY HELD CONCEPTS ARE CALLED INTO QUESTION • MOST BELIEVED THAT THE CONCEPT OF THE EQUANT WAS INCORRECT. PLANETARY MOTION HAD TO BE UNIFORM • ARISTOTLE IDEAS ARE QUESTIONED • COULD THE EARTH ACTUALLY BE ROTATING? • HIS LAWS OF INERTIA WERE CLEARLY WRONG • FOR EXAMPLE, AN ARROW SHOT INTO THE AIR CONTINUED TO RECEDE FROM THE EARTH AFTER IT HAD LEFT THE BOW. ARISTOTILEAN PRECEPTS SUGGESTED THAT, SINCE THE ARROW WAS “EARTH” IT SHOULD IMMEDIATELY SEEK THE EARTH • ARISTOTLE SUGGESTED THAT AIR SUPPLIED THE FORCE THE CAUSED THE ARROW TO CONTINUE TO RISE

15. MEDIEVAL LATIN ASTRONOMY • JEAN BURIDAN (c. 1295 – c. 1358) AND NICOLE ORESME (c. 1320 – C. 1382) SUGGESTED THAT AIR WAS NOT THE FORCE BUT “IMPETUS” (WHAT WE WOULD CALL MOMENTUM) PROVIDED BY THE BOW SUPPLIED THE FORCE. • BURIDAN ARGUED THAT, IF THE EARTH WERE ROTATING, IT WOULD MOVE THE ARCHER AS WELL AS THE ARROW AND THAT ONE COULD NOT TELL FROM SUCH AN EXPERIMENT WHETHER THE EARTH ROTATED • BURIDAN BELIEVED THAT THE EARTH WAS FIXED

16. MEDIEVAL LATIN ASTRONOMY • BURIDAN ALSO DISAGREED WITH THE ARISTITOLEAN IDEA THAT “GOD” OR “GODS” SUPPLIED THE FORCE(S) THAT KEPT THE CELESTIAL SPHERE TURNING • HE SAID THAT, IN THE ABSENCE OF FRICTION, NO FORCE WOULD BE NEEDED – IMPETUS WOULD KEEP IT TURNING • THIS LOOKS VERY MUCH LIKE NEWTON’S “FIRST LAW”

17. MEDIEVAL LATIN ASTRONOMYTHE RENAISSANCE APPROACHES • GUTENBURG DEVELOPS THE PRINTING PRESS IN 1450 • THE GUTENBURG BIBLE IS PUBLISHED IN 1455 • WITH PRINTING SCRIBES’ ERRORS CEASED • JOHANNES BESSARION (c. 1395 – c. 1472), GEORG PEURBACH (1422–1461) AND JOHANNES MULLER OF KONIGSBERG (1436-1476) COLLABORATED TO PUBLISH A NUMBER OF ASTRONOMICAL TREATISES. • PEURBACH WROTE NEW THEORIES OF THE PLANETS • MULLER OVERSAW IT’S PRINTING AFTER PEURBACH’S DEATH • BESSARION SET OUT TO PRINT AN ABRIDGED VERSION OF THE ALMAGEST – HE SUCCEDED IN PRINTING ONLY SIX VOLUMES • MULLER OVERSAW IT’S PRINTING AFTER BESSARION’S DEATH • BERNARD WALTHER (1430-1504), A MERCHANT IN NUREMBERG, BUILT ON MULLER’S WORK AND PRODUCED A NUMBER OF OBSERVATIONS LATER USED BY COPERNICUS, TYCHO AND KEPLER