Ptolemy of Alexandria, the Influential Astronomer
Ptolemy of Alexandria was the most influential astronomer of the
ancient world. The books and theories Ptolemy developed served as a major
basis for future astronomers. It was during the Renaissance period that
his work became thoroughly studied and revised.
Ptolemy collected all ancient knowledge of astronomy and geography
including it in his book Almagest around 140 A.D. It follows, he then
wrote a four volume astrological study known as the Tretrabiblos. Ptolemy
claimed that the scribes of Babylon had been instructed since 750 B.C to
keep detailed astronomical diaries. These diaries were written for seven
hundred years on clay tablets. The tablets depicted night-sky events along
with river level changes and weather phenomena. Modern archaeologists have
confirmed the claim by unearthing Babylonian tablets recording observations
of Mars and Venus from that time period.
Ptolemy used a method of consulting lists of lunar phases, and
planetary movements complied over many centuries to look for any
similarities or regular patterns. The patterns that were discovered could
then predict the next occurrence of such an event. Ptolemy eventually
devised an ancient form of nautical almanac or "ephemeris". Mathematics
could now not only be used to predict but to demonstrate whether a
particular theory was correct or not.
Ptolemy developed several theories of his own contrary to the beliefs
of many other Greek astrologers at the time. He upheld that the "heavens"
consisted of bodies orbiting the earth in a celestial path - this idea was
supported for some time. Though his views were altered by the...