By Nick Bobish and Bree Balsamo
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His full name is Claudius Ptolemaeus. While there are a
lot of theories, no one is sure when he was born or
where he died and this reflects in his personal life too.
He is a Greek Egyptian astronomer, mathematician and
geographer during the Hellenistic era.
He is most famously known for living in Alexandria,
Egypt where he made most of his astronomical
observations.
He is also a writer and is know for writing about the
subjects of geography, astrology, musical theory, optics,
physics, and astronomy.
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Using Hipparchus's system of epicycles and eccentric
circles and his knowledge about Earth being a sphere,
Ptolemy formed his own explanation about his
geocentric theory of the solar system.
His system involves over 80 epicycles. These epicycles
are used to show explain the motions of the Sun, Moon,
and the five planets known during his time. (Mercury,
Venus, Sun, Mars, Jupiter, Saturn)
This system became known as the Ptolemaic system.
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This system can accurately predict the positions of the
planets without the need for a telescope. This is
mentioned in his well known book, the Almagest.
The Almagest itself is a series made of 13 volumes that
applies mathematics to astronomy.
It contains information about many subjects, from
earth conceptions, the movements of the sun, moon,
and stars, eclipses and the breakdown on the length of
months. Lastly it contains a star catalog containing 48
constellations, using the names that are still used today.
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Geographica (Geography) contained most of the
information on geography that was collected by the Greeks
and the Romans.
It is a work of seven volumes and remained the standard
geography textbook until the 15th century. In modern times
it is the equivalent to an ancient atlas.
It contains a world map, 26 regional maps and 67 maps for
smaller areas. In this collection of map, three different
methods for projecting the Earth’s surface is shown. (an
equal area projection, a stereographic projection, and a
conic projection)
Ptolemy also included directions on how to draw the
spherical world on a flat map.
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Mentioned before, Ptolemy discovered or developed
the concepts of latitude and longitude and knew how to
locate nearly 8,000 areas on the world by using
longitude and latitude.
When creating his maps, Ptolemy placed the directions
North on top and East on left. Now this orientation has
become a standard for all maps.
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Because of Ptolemy’s work, he inspired explorers, such as
Christopher Columbus to voyage to unknown places.
Most navigation or factual maps used by early European explores
were formed by copies and reprints of Ptolemy’s world maps.
Ptolemy’s theory remained wildly accepted dominated European
cartography until 1543 a man named Copernicus created the
heliocentric view.
The system Ptolemy created is actually more accurate than
Copernicus's and is not notably improved until Kepler's Laws are
added along with Copernicus’s idea.
Even though many of Ptolemy’s theories have been changed or
proven wrong over the centuries, his works are still famous and
became the foundation for future generations.
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http://obs.nineplanets.org/psc/theman.html
http://www.csiss.org/classics/content/76