HISTORY OF ASTRONOMY - Rodolfo Angeloni's Webpage...19/05/2014 History of Astronomy And further, to help the moon, that it may not fall, there is its motion itself and the whizzing

HISTORY OF ASTRONOMY Historia de la Astronomía

Curso optativo de profundización AST1521 – ASP5021

Semestre 2014 A Lunes-Miércoles h 14-15;20

Sala N2 – Campus San Joaquín

Instituto de Astrofísica Pontificia Universidad Católica de Chile

Rodolfo Angeloni

19/05/2014 History of Astronomy

DÍA DE LAS GLORIAS NAVALES Míércoles 21 de Mayo

NO HAY CLASE

Se recupera el Jueves 22 de Mayo a las 13hs

NEXT ACTIVITIES


Lunes 2 de Junio Auditorium Bralic, 14hs

Clase en videoconferencia desde el Observatorio ESO de la Silla

NEXT ACTIVITIES


DÍA DEL PATRIMONIO – OBSERVATORIO FOSTER 25 de Mayo, 10-16 hs

NEXT ACTIVITIES


o The Antikythera Mechanism – Guerrero & Zuñiga o The Archimedes’ Palimpsest – Henriquez & Vargas o About Aristarchus’ “On sizes and distances” – Collao & Walker o “Ptolemy’s Longitudes…” - Herrera & Vergara

NEXT ACTIVITIES

Seminarios – 2nd round Miércoles 28 de Mayo – (15+5) min X 4 grupos

19/05/2014

NEXT ACTIVITIES

Invited Lecturer Miércoles 04 de Junio

History of Astronomy

“El conocimiento histórico y sus metodologías”

Prof. Ana Francisca Viveros Gonzalez USACH - Facultad de Humanidades, Dept. de Historia

19/05/2014

NEXT ACTIVITIES

Invited Lecturer Miércoles 11 de Junio

“ La dimensión histórica de la ciencia, y su relación con la epistemología contemporánea”

Prof. Luis Flores Hernández Facultad de Filosofía, PUC


19/05/2014

NEXT ACTIVITIES

Invited Lecturer Lunes 16 de Junio

“ Breve Historia de la Astronomía en Chile en los siglos XIX & XX”

Prof. Hernán Quintana Instituto de Astrofísica, PUC



LOST SCIENCE

Aristarchus of Samos brought out a book consisting of some hypotheses, in which the premises lead to the result that the cosmos is many times greater than that now so called. His hypotheses are that the fixed stars and the Sun remain unmoved, that the Earth revolves about the Sun in the circumference of a circle, the Sun lying in the middle of the orbit, and that the sphere of the fixed stars, situated about the same center as the Sun, is so great that the circle in which he supposes the Earth to revolve bears such a proportion to the distance of the fixed stars as the center of the sphere bears to its surface.

Archimedes, Arenarius


Was [Timaeus] giving the earth motion . . . , and should the earth. . . be understood to have been designed not as confined and fixed but as turning and revolving about, in the way expounded later by Aristarchus and Seleucus, the former assuming this as a hypothesis and the latter proving it…

Plutarch, Platonicae quaestiones, 1006C

LOST SCIENCE


And further, to help the moon, that it may not fall, there is its motion itself and the whizzing nature of its rotation, just as objects placed in a sling are prevented from falling by the circular motion. For each body is guided by motion according to nature, if it is not turned aside by something else. For this reason the moon does not follow its weight, which is cancelled by the counterweight of the rotation. There would perhaps be much greater reason to marvel if it kept motionless and still like the earth […]

Plutarch (46-125 AD), De facie quae in orbe lunae apparet, 923C-D

LOST SCIENCE


Of these five stars [i.e., the planets], which display themselves to us and

which pique our curiosity by appearing now here now there, we have recently started to understand what their morning and evening risings are, where they stop, when they move on a straight line, why they move backward; we learned a few years ago whether Jupiter will rise or sink or retrograde (for this is the name given to its backward movement).

Seneca, Naturales Quaestiones, VII, XXV, 5 62-63 AD

LOST SCIENCE


There are some who have told us: “You are mistaken in thinking that any star stops on its track or turns backward. Heavenly bodies cannot be detained or turned back; they forever move forth; as they once were sent on their way, so they continue; their path does not end but with their own end. This eternal work has irrevocable motions: if ever [these bodies] stop, they will fall upon one another, for it is constancy and evenness that preserve them now. Why is it then that some of them seem to turn back? The appearance of tardiness is caused by the intervention of the sun (solis occursus), and by the nature of their paths and circles, so arranged that for a certain time they deceive the observer: just as ships, though moving under full sail, appear stationary…”

Seneca, Naturales Quaestiones, VII, XXV, 6-7 62-63 AD

LOST SCIENCE


LOST SCIENCE - THE END OF HELLENISM

Histogram of astronomical observations referred to in Ptolemy's Almagest. Each bin is a 20-year period centered on January 1 of the year indicated.

The number of observations is written on top of selected bars.


THE END OF HELLENISM

Starting with the year 212 B.C., which witnessed the plunder of Syracuse and the killing of Archimedes, Hellenistic centers were defeated and conquered by the Romans. During the second century B.C. scientific studies declined rapidly. Alexandria's scientific activity, in particular, stopped abruptly in 145–-144 B.C., when Ptolemy VIII (Euergetes II), who had just ascended the throne, initiated a policy of brutal persecution against the city's Greek ruling class.


THE END OF HELLENISM

After the interruption caused by the wars with Rome, the Pax Romana allowed a partial resumption of scientific research in the first and second centuries A.D.— (the time of Heron, Ptolemy and Galen)—, after which the decline was unstoppable. For another couple of centuries, Alexandria remained the center of what scientific activity there was.

Among the commentators and editors of that time it is worth mentioning Pappus, whose Collection brings together many mathematical results that have not reached us otherwise, and Theon of Alexandria, whose editions of Euclid's Elements and Optics have survived through the centuries.

The activity documented in the IV century A.D. is limited to compilations, commentaries and rehashings of older works.


THE “RENAISSANCES”

One of these first “revivals” occurred around the early VI century A.D. and had as its protagonists Simplicius, John Philoponus, Eutocius, Anthemius of Tralles and Isidore of Miletus.

The memory of Hellenistic science survived thanks to a series of revival periods when interest in ancient knowledge was rekindled

for a time in a certain geographical area

History of Astronomy 19/05/2014


CULTURAL CROSSES

Probably, when the cultural center of gravity shifted from Alexandria to Byzantium, scholars became acquainted with works preserved in the East which had never been part of the Alexandrian tradition.

Cultural exchanges with Eastern countries that had stayed outside the Roman empire are illustrated by a famous episode. When Justinian had the Athenian philosophical academy closed in 529, the Sassanid king Chosroes I invited the newly unemployed philosophers to his Persia; among those who accepted were Simplicius, Damascius (who was head of the academy at the time it closed) and Priscian of Lydia.




ISLAMIC CALIPHATES

Rashidun Caliphate (632–661) Umayyad Caliphate (661–750) Abbasid Caliphate (750–1258)

Ottoman Caliphate (1517–1924)


ISLAMIC RENAISSANCE Harun al-Rashid الرشيدهارون ‎

(766-809)


ISLAMIC RENAISSANCE Abu Jaʿfar Abdullah al-Maʾmun ibn Harun

المأمونابوجعفر عبدهللا (786-833)


THE HOUSE OF WISDOM

A page from al-Khwarizmi's Kitab al-Jabr Scholars at an Abbasid library - Baghdad 1237


ISLAMIC ASTRONOMY Astronomy and Islamic practices

Religious practices generated three specific challenges to which mathematical astronomers attempted solutions, the complexity of which often went beyond the actual needs of the community.

o Lunar calendar o Daily times of prayer o Direction to Mecca (qibla)



ISLAMIC ASTRONOMY Abu ʿAbdallah Muhammad ibn Musa al-Khwarizmi

(780-850)

A page from the al-Khwarizmi's Zij

A Zij is a collection of astronomical tables with instructions for their use, composed in the tradition of Ptolemy’s Handy Tables.

19/05/2014

ISLAMIC ASTRONOMY Muhammad ibn Jabir al-Harrani al-Battani

(858-929)

al-Battani’s zij is written with the explicit conception that astronomy is a science that requires observations as a test of theory

Al-Battani refined existing values for the length of the year and of the seasons, for the annual precession of the equinoxes, and for the inclination of the ecliptic. He showed that the position of the Sun’s apogee is variable.



ISLAMIC ASTRONOMY Arabic Planetary Astronomy

Nasir al-Din Tusi (1201-1274)

“Let us set forth . . . a lemma, which is as follows: if two coplanar circles, the diameter of one of which is equal to half the diameter of the other, are taken to be internally tangent at a point, and if a point is taken on the smaller circle – and let it be the point of tangency – and if the two circles move with simple motions in opposite directions in such a way that the motion of the smaller [circle] is twice that of the larger so the smaller completes two rotations for each rotation of the larger, then that point will be seen to move on the diameter of the large circle that initially passes through the point of tangency, oscillating between its endpoints.”

Nasir al-Din Tusi, Memoir on Astronomy The Tusi couple




The Tusı couple had profound consequences since it undermined the Aristotelian distinction between circular celestial motions and rectilinear terrestrial motion. Using this device, astronomers were able to modify Ptolemy’s geometrical models so as to remove the need for either an eccentric deferent or an equant.




The Tusı couple had profound consequences since it undermined the Aristotelian distinction between circular celestial motions and rectilinear terrestrial motion. Using this device, astronomers were able to modify Ptolemy’s geometrical models so as to remove the need for either an eccentric deferent or an equant.




The means of replacing an eccentric motion by Tusi-style devices



Ibn al-Shatir (1304-1375)

Ibn al-Shatir theory for the superior planets



Ibn al-Shatir (1304-1375)

As far as accuracy was concerned, the Ibn al-Shatir models did not improve on those of Ptolemy, but simply removed the equants.

“I therefore asked Almighty God to give me inspiration and help me to invent models that would achieve what was required, and God - may He be praised and exalted, all praise and gratitude to Him - did enable me to devise universal models for the planetary motions in longitude and latitude and all other observable features of their motions, models that were free - thank God from the doubts surrounding previous models.”

Ibn al-Shatir’s zij


ISLAMIC ASTRONOMY 'Abd al-Rahman al-Sufi

(903-986)

“Book of the fixed stars”


Coordinates precessed from Ptolemy’s catalogue to the epoch AD 964

Own brightness measurements 1151 stars with a brightness probable error of ±0.38 mag

STAR CATALOGUES Al-Sufi’s star catalogue in the “Book of the fixed stars”


STAR CATALOGUES Ptolemy’s Star Catalogue

Coordinates for the epoch AD 137

Own brightness measurements 1022 stars with a brightness probable error of ±0.37 mag


STAR CATALOGUES ¿How to measure star magnitudes?


STAR CATALOGUES ¿How to measure star magnitudes?

www.aavso.org/files/publications/vstelescope.ppt‎

mailto:www.aavso.org/files/publications/vstelescope.ppt‎

Documents

HISTORY OF ASTRONOMY - Rodolfo Angeloni's Webpage...19/05/2014 History of Astronomy And further, to help the moon, that it may not fall, there is its motion itself and the whizzing