3 edition of From deferent to equant found in the catalog.
From deferent to equant
|Statement||edited by David A. King and George Saliba.|
|Series||Annals of the New York Academy of Sciences ;, v. 500|
|Contributions||Kennedy, E. S. 1912-, King, David A., Saliba, George.|
|LC Classifications||Q11 .N5 vol. 500, Q124.97 .N5 vol. 500|
|The Physical Object|
|Pagination||xxix, 569 p. :|
|Number of Pages||569|
|LC Control Number||87011312|
Equant (or punctum aequans) is a mathematical concept developed by Claudius Ptolemy in the 2nd century AD to account for the observed motion of the planets. The equant is used to explain the observed speed change in planetary orbit during different stages of the orbit. This planetary concept allowed Ptolemy to keep the theory of uniform circular motion alive by stating that the path of. Figure 2. In the concentric equant model the Earth is at the center O of a deferent of radius R and the planet is at S on the deferent. The motion of S is uniform as seem from the equant point E, which is a distance e from O. 3 R. & D. Lawlor, Theon of Smyrna: Mathematics Useful for Understanding Plato Or, Pythagorean Arithmetic, Music, Astronomy.
The Almagest (/ˈælməˌdʒɛst/) is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy (c. AD – c. ). One of the most influential scientific texts of all time, its geocentric model was accepted for more than years from its origin in Hellenistic Alexandria, in the medieval. Equant Ptolemy placed the earth offcenter and the opposite point from the deferent on this off center circle is called the equant. Equatorial Mounting. equant: The point off-center in the deferent from which the center of the epicycle appears to move uniformly. equatorial mounting: A telescope mounting that allows motion parallel to and perpendicular to the celestial equator.
The basic elements of Ptolemaic astronomy, showing a planet on an epicycle (smaller dashed circle), a deferent (larger dashed circle), the eccentric (×) and an equant (•).. Equant (or punctum aequans) is a mathematical concept developed by Claudius Ptolemy in the 2nd century AD to account for the observed motion of the planets. The equant is used to explain the observed speed change in. FROM DEFERENT TO EQUANT: A VOLUME OF STUDIES IN THE HISTORY OF SCIENCE IN THE ANCIENT AND MEDIEVAL NEAR EAST IN HONOR OF E.S. KENNEDY Editors DAVID A. KING AND GEORGE SALIBA CONTENTS Editors' Preface ix E.S. Kennedy: A Brief Biography. By the Editors xiii List of Publications of E.S. Kennedy xvii The Collected Papers of E.S. Kennedy: A Brief.
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Goodreads helps you keep track of books you want to read. Start by marking “From Deferent to Equant: A Volume of Studies on the History of Science of the Ancient & Medieval Near East in Honor of E. Kennedy” as Want to Read:3/5(2). From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E.S.
Kennedy (Annals of the New York Academy of Sciences) by David A. King (Author) › Visit Amazon's David A. King Page. Find all the books Cited by: From deferent to equant. New York, N.Y.: New York Academy of Sciences, (OCoLC) Named Person: E S Kennedy; E S Kennedy: Material Type: Internet resource: Document Type: Book, Internet Resource: All Authors / Contributors: E S Kennedy; David A King; George Saliba.
Book Review: From deferent to equant: a volume of studies in the history of science in the ancient and medieval near east in honor of E. Kennedy. / New York Academy of Sciences, North, J.
From deferent to equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E. Kennedy Book February with Reads How we measure 'reads'. The centre of the deferent is midway between the equant and Earth.
Encyclopædia Britannica, Inc. Learn about this topic in these articles: definition by Ptolemy. In Ptolemaic system point that he called the equant. The centre of the deferent was located midway between the equant and the Earth, as can be seen in the figure. From Deferent to Equant: A Volume of Studies on the History of Science of the Ancient and Medieval Near East in Honor of ES Kennedy Pages: ix-xxix, June From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval near East in Honor of E.S.
Kennedy: Published Date: Book Condition: Very good: Jacket Condition: No Dustjacket: Binding: Paperback: Size: 8vo: Place of Publication: New York: Edition: First edition: Category: Science: Author: David A. King. Placement. The equant point (shown in the diagram by the large •), is placed so that it is directly opposite to Earth from the deferent's center, known as the eccentric (represented by the ×).
A planet or the center of an epicycle (a smaller circle carrying the planet) was conceived to move at a constant angular speed with respect to the equant. In other words, to a hypothetical observer.
Book-Review - from Deferent to Equant - History of Science in the Ancient and Medieval Near East in Honor of Kennedy, E.S. Placement. The equant point, indicated in the diagram by the large •, is placed so that it is directly opposite the Earth from the center of the deferent (known as the "eccentric"), indicated by the X.A planet or the center of an epicycle (a smaller circle carrying the planet) was conceived to move with a uniform angular speed with respect to the equant.
Claudius Ptolemy refined the deferent-and-epicycle concept and introduced the equant as a mechanism for accounting for velocity variations in the motions of the planets. The empirical methodology he developed proved to be extraordinarily accurate for its day.
The epicycle rotated and revolved along the deferent with uniform motion. However Ptolemy found that the rate at which the deferent revolved was not constant unless he measured it from another point at an equal distance from the eccentric, which he called the equant.
It was the angular rate at which the deferent moved around the equant that was. Buy From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E.S. Kennedy on. The angular rate at which the epicycle traveled was not constant unless he measured it from another point which he called the equant.
It was the angular rate at which the deferent moved around the point midway between the equant and the Earth (the eccentric) that was constant; the epicycle center swept out equal angles over equal times only. A little way along this line from the Earth point is a point marked 'centre of deferent'.
At the same distance further along the line is a point marked 'equant'. There is a circle marked 'Deferent' which is drawn centred on the point marked 'centre of deferent'.
A red line from the 'Earth' point is drawn to the point marked 'equant'. Ptolemaic system Ptolemy's equant modelIn Ptolemy's geocentric model of the universe, the Sun, the Moon, and each planet orbit a stationary Earth.
For the Greeks, heavenly bodies must move in the most perfect possible fashion—hence, in perfect circles. In order to retain such motion and still explain the erratic apparent paths of the bodies, Ptolemy shifted the centre of each body's orbit.
Buy From Deferent to Equant: Volume of Studies on the History of Science of the Ancient and Mediaeval Near East in Honour of y (Annals of the New York Academy of Sciences) by King, David A., Saliba, George (ISBN: ) from Amazon's Book Store.
Everyday low prices and free delivery on eligible : David A. King. Ptolemy said the deferent does NOT move around the eccentric at a uniform speed. He added a different imaginary point – the equant – the white dot to the left of the eccentric on the diagram above.
The equant is twice as far from Earth as the eccentric. Ptolemy said the deferent moves around the equant at a uniform speed. The angles of the blue lines from the equant remain 45 degrees apart, but the planetary positions change as the white circle they are on moves, which then changes where they appear to be as the earth watches them.
Now, watch what happens to the retrogressions map as we go from the off-center circle, to the equant. P Kunitzsch, al-Khwarizmi as a source for the 'Sententie astrolabii', in From deferent to equant (New York, ), G P Matvievskaya, The algebraic treatise of al-Khwarizmi (Russian), in On the history of medieval Eastern mathematics and astronomy (Tashkent, ), an epicycle, which is a smaller circle that a planet moves along as its orbit travels the deferent, and an equant, which is the amount that the center of the deferent is offset from Earth’s.Emilie Savage-Smith, "From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E.
S. Kennedy. David A. King, George Saliba," I no. 1 (Mar., ):