Astronomy

Egyptian astronomy
    solar calender: 12 X 30 + 5 =365: used by Ptolemy
        twelve months of 3 decades (decans) each; then imposed on the ecliptic as constellations or parts of constellations in the Middle Kingdon (decans later refer to 10 degrees under influence of Hellenistic astronomy)
    heliacal rising of Sirius as harbinger of the flood of the Nile
    division of day into 24 hours;  12 of day; 12 of night; different length until Hellenistic theoretical ‘equinoctial hour’; then divided in Bab fashion sexagesimally, for modern time

Mesopotamian Astronomy
    temple priests maps fixed and 5 wandering stars
    complete list of lunar eclipses since Nabonassar 747BCE
    500 BC Babylon identified the zodiac and constellations in 12 segments
        which could be used to chart planets
    astrology was a major motivator - astral religion
        development of judicial astrology - predicting things for the king
        in contrast to horoscopic
    astrology transmitted to Greeks, Persians, Romans, Middle Ages and Modern Period
    500-300 - numerical models to chart movements - i.e. not geometrical models as with the Greeks
    arithmetical progressions to chart periodically variable phenomena
    predict appearance of new moon, lunar eclipses and possible/impossible solar eclipses
    19 year lunar-solar cycle
        such period relations are very important in Babylonian astronomy


43- Thales (fl. 585) is most unlikely to have pioneered astronomical science: Babylonians and Egyptians had no science, only experience
-his knowledge was not much different from Hesiod's
-may have known the 18 yr cycle of eclipses
    planets – wanderers

Anaxagoras (mid-late 400s): determined the cause of the eclipse of the moon
    also determined that the moon shines by reflected light from the sun
Meton rectified the solar-lunar calender of Athens
    since a year has between 12 and 13 months in it
    Metonic cycle (late 400s): 235 lunar months = 19 years
    
Euktemon : inequality of the seasons of the year
    the fall and winter are shorter than the spring and summer in the northern hemisphere
Eudoxus (c.355):
    Plato asks his mathematicians to model the celestial motions on circular motions
    Eudoxus devised a concentric spheres model with the earth at the center
    took account of retrograde motion of the planets
Callippus refined the Metonic cycle, giving year 365 ¼ days
    and refined Eudoxus’ model
 and Aristotle made Eudoxus’ spheres physical rather than merely mathematical