Ptolemy of Alexandria, the Influential Astronomer Essays

He was the first person whose systematic use of trigonometry has documentary evidence, which is presented from Ptolemy and Theon of Alexandria. For example, he is responsible for the division of a circle into 360 degrees, the creation of one of the first trigonometric tables for solving triangles, and the precepts of trigonometry. The table showed how each degree divided into 60 minutes, which made the radius 360.60/2π = 3438 minutes and the chord function Crd of Hipparchus is related to the sine function by (Crd 2a)/2 = 3438 sin a. The table of chords, explained in 12 books, is used as a method to solve triangles without having to solve each triangle from first principles. As an astronomer, he calculated the length of the year to within 6.5 minutes. He also discovered the precession of equinoxes with a value of 46 degrees, which is fairly close to the modern number of 50.26 degrees. The precession of the equinoxes, or the gradual shift in Earth’s rotation axis, demonstrates how the earth wobbles like a top as it spins, which indicates there is a shift in point of direction of the poles over time. Hipparchus’s calculations are able to explain why the north star changes throughout a 26,000-year cycle; at some point of time it was Thuban, Beta Ursae Majoris, and the Polaris star is the north star now. In addition, he charted the sky with 850 stars and motions of the moon. These are

During the first millennium B.C. scientists realized that astronomy had to become more scientific. Middle Eastern and Chinese cultures started studying the Sun, stars and the planets more closely in an attempt to learn more about our position in the universe.. Star positions also became important tools in understanding directions, and helping with navigation. One philosopher stated in 434 B.C. that the Sun was a ball of fire 60 kilometres in diameter, hovering 6500 kilometres above Earth’s surface. Around 130 B.C., Ptolemy wrote Almagest, which was a huge collection of astronomical data which included mathematical models, information about eclipses, and planetary and stellar positions and movements. It remained a major go to book for astronomy for hundreds of years, and was not seriously challenged until Copernicus disputed the geocentric model of the solar system in the 1500’s

Moreover, the transfer of ideas also had an intellectual impact in fields such as astronomy, medicine, and mathematics. To begin with, Claudius Ptolemy, a Greek scholar, created a model of how the solar system is arranged, the Earth in the center (document one). Claudius Ptolemy most likely described the inverse with the Earth in the center because of the limited technology during his time period, some time around 100 AD. Persian Muslim scholar, Al-Biruni, describes the Hindu view of how the earth is shaped and that the earth is the center of the universe (document six). Al-Biruni is a Persian Muslim and not a Hindu and therefore writes about these conceptions with the point of view of an outsider. During this time period, various scholars came up with

In other words Claudius Ptolemy was an astronomer who was born during the year 85 AD . He spent most of his life studying how the Earth, Planets, and Sun moved. He was one of the very first astronomers so, not very much was known. A lot of people doubted him because in his time religion was very important and they thought that they only thing you couldn't see with the naked eye was Heaven and hell. His first time he published his observation was on March 26th 127. He spent almost 20 years getting his theory to make sense. He knew people wouldn't believe him so he broke down his discovery into thirteen books and each book was a part of his discovery. After he published his first one he was able to do a couple small ones, but sadly, the last of his discoveries was made on

The Hellenistic time period created the foundation for many modern ideas regarding, in particular, the topics of Astronomy and Medicine. These ideas could be found throughout the study of the size and distance of the sun and moon or the learning of human anatomy. Ancient philosophers used many techniques to study the many aspects of the world. Many of these techniques resemble scientific methods used today.

One of the beliefs that shifted during the Renaissance was that people realized the solar system was heliocentric. Ptolemy, who lived in Alexandria, Egypt, came up with the geocentric universe where the sun and all the planets revolve around the Earth. In his universe, there is also a home for their Deity in the outer rings. Later, Copernicus created the heliocentric universe model with the sun at the center and all the planets revolving around it. Ptolemy represents the pre-Renaissance thinking that the world had at the time.

The geocentric model created by Ptolemy, and the heliocentric model created by Copernicus, had greatly differed in which force of being (the sun or the earth,) was the center of the universe. Ptolemy’s Geocentric

theory that the sun is at rest near the center of the universe, and that the

Johannes Kepler was a mathematician, an astrologer, and an astronomer. He was a key figure in the 17th century scientific revolution and was best known for his laws of planetary motion.

Jacob Holleran Mr. Corso Astronomy Period 5 1/15/18 CLAUDIUS PTOLEMY Claudius Ptolemaeus (Ptolemy) was an influential Greco-Roman astronomer who made important contributions to the sciences in his lifetime during the first century. He contributed to the studies of astronomy, cartography, and optics. Ptolemy developed the eventually disproven Geocentric theory, which falsely claimed that the earth was the center of the solar system, and that the other planets and the sun orbited around it. Regardless, his scientific contributions were influential for centuries to come, and formed the basis for the astronomy of the middle ages. He is regarded as one of the most influential scientist in history.

Many ancient civilizations had their own beliefs about the stars and the universe. Some examples of these intelligent civilizations were the Ancient Babylonians, Middle Eastern civilizations, Central American civilizations, Ancient Chinese, and the Ancient Greeks. The Ancient Babylonians studied patterns on Venus which were later continued by Galileo and Copernicus. People from the Middle East, Central America, and China watched the skies and made many observations and predictions of movement in the heavens. There were many famous Philosophers and Astronomers from the Ancient Greek civilizations who studied the sky. They searched for patterns and numbers to find something fundamental. Thinkers attempted to come up with combinations of uniform circular motions that would prove their already observed irregular motions. Aristotle was a Greek philosopher who thought that the moon, sun, and other planets rotated around the stationary Earth. But, as we know today, his theory was incorrect. Some other Greek philosophers attempted to measure the distance to the moon and even tried to find the size of the universe! They found the universe to be finite. On the other and, Claudius Ptolemy believed that the heavens (skies) were not made of rocks, metal, or other Earthy materials, but that they were made of

About two centuries after Aristotle, Hipparchus showed that the model better predicted the motion of the heavens if the Earth was placed slightly off the centre of rotation of the celestial spheres. Apollonius also proposed that the planets changed their speed through the heavens and sometimes stopped and travelled backwards.

This was a major breakthrough in astronomy, and their heliocentric concept predates Copernicus by about 1100 years. It is speculated that the Indians might have even discovered the heliocentric theory earlier than this, because in 3000 B.C, early Vedic writings suggest the Sun to be the center of the universe after all. A popular ancient Indian astronomer was Ayrabhatta. Ayrabhatta became one of the most well-known ancient Indian astronomers due to not only his historical findings on common astronomical occurrences, but because his books were translated into Latin and heavily influenced European astronomers to develop his findings even further. He advanced upon the speculated heliocentric theory, presented a mathematical system depicting the Earth to spin on an axis, and theorized how the lunar and solar eclipses came to be. His book, the Ayrabhattiya, published in 498 AD, advanced on the leads from the cyclic Hindu cosmology. It was through his work, and the work of several others, that there were leads on the theory of

Johannes Kepler was a German astronomer and mathematician who lived between 1671-1630. Kepler was a Copernican and initially believed that planets should follow perfectly circular orbits (“Johan Kepler” 1). During this time period, Ptolemy’s geocentric theory of the solar system was accepted. Ptolemy’s theory stated that Earth is at the center of the universe and stationary; closest to Earth is the Moon, and beyond it, expanding towards the outside, are Mercury, Venus, and the Sun in a straight line, followed by Mars, Jupiter, Saturn, and the “fixed stars”. The Ptolemaic system explained the numerous observed motions of the planets as having small spherical orbits called epicycles (“Astronomy” 2). Kepler is best known for introducing three

Sarah Williams, an old English poet wrote this quote, "I have loved the stars far too long to be fearful of the night." Found in her famous poem called, "The Old Astronomer to his Pupil." Weather you love the poem or just find the quote refreshing, this piece can be meaningful in many different ways, depending on the individual. Hang this acrylic painting up on your wall at home or even give it as a gift to someone special!