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Al-Farghani, Alfraganus, Amateur Astronomer, Amateurs, Anders Angstrom, Arecibo Observatory, Asteroid Belt, Asteroid,
Astronomical, Astronomy, Atacama, Bernhard Schmidt, Big Horn Medicine Wheel, Black Hole, Bolide, Brian Timmins,
Brians Timelines, brianstimelines, CADC, Cahokia Mounds, Caltech, June 2000, Cambridge University,
Canadian Astronomy Data Centre, Carl Sagan, Carl Seyfert, Cerro Tololo Interamerican Observatory, Chaco Canyon,
Chandra Chankillo, Charles Messier, Chichen Itza, Chris Lintott, Christiaan Huygens, Chronological Facts, Chronological,
Chronology, Clyde Tombaugh, Comet, Copernicus, CTIO, DAO, Dark Matter, Dominion Astrophysical Observatory,
Dominion Radio Astrophysical Observatory, DRAO, Dwarf Planet, Earth, Edmond Halley, Edwin Hubble, Einstein, Ejnar Hertzsprung,
ESA, ESIS, ESO, European Southern Observatory, European Space Information System, Events, Fajata Butte, Fred Hoyle, Fritz Zwicky,
Galactic, Galaxy, Galileo Galilei, Galileo, Gemini, George Hale, Gerard Kuiper, Giovanni Cassini, GLAST, Goseck Circle,
Gravity Lens, Gravity Lensing, Gravity, Halley, Historical Event, History, HST Astrometry Science Team, Hubble,
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Jet Propulsion Laboratory, Johannes Kepler, Joseph Von Fraunhofer, Joseph-Louis Lagrange, JPL, Jupiter, Karl Schwarzchild,
Keplers Laws, Kitt Peak National Observatory, KPNO, Kuiper Belt, Las Campanas And Magellan, Las Campanas Observatory,
Light Year, Machu Picchu, Magellan Project, Mars, Mauna Kea, Mcdonald Observatory, Mercury, Meteor, Meteorite,
Meteoroid, Milky Way, MIT, Moon, Mount Stromlo And Siding Springs Observatories, Mount Wilson Observatory, MSO & SSO,
NASA, National Aeronautics And Space Administration, National Astronomy And Ionosphere Center,
National Observatory Of Japan, National Optical Astronomy Observatories, National Radio Astronomy Observatory,
National Solar Observatory, Nebula, Nebulae, Neptune, Neutron Star, Newgrange, Newton, Nicolaus Copernicus, Night Sky, NOAO,
Nova, NRAO, NSO, Observation, Observatories Of The Carnegie Institution Of Washington, Observatory, Oort Cloud, Parsec,
Patrick Moore, Planets, Pluto, Ptolemaiac, Ptolemaic, Ptolemy, Pulsar, Quark Star, Quasar, Royal Greenwich Observatory,
Sacramento Peak, SAO, Saturn, Search For Extra Terrestrial Intelligence, SETI, Sir Fred Hoyle, Sir Isaac Newton, Sir Patrick Moore,
Site, Sky At Night, Smithsonian Astrophysical Observatory, SOHO, Solar System, Space Telescope Electronic Information System,
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Subramanyan Chandrasekhar, Sunspot, Supernova, Gemini 8M Telescopes Project, Miami Circle, Temple At Karnak,
Very Large Telescope Project, Theory Of Relativity, Time Line, Time Scale, Time, Time-Lines, Timeline, Timelines, Timescale,
Timmins, Tycho Brahe, U.Mass Amherst, UKIRT, United Kingdom Infra-Red Telescope, University Of Massachusetts Astronomy,
University Of Texas Department Of Astronomy, Uranus, Ut-Austin, Venus, Virtual Observatory Conference, VLT,
Wallace Astrophysical Observatory, William Herschel, Woodhenge,
Lunar Distance, Astronomical Unit, Light Year, Parsec, Newton's Laws Of Motion, Solar Mass, Event Horizon,
Keplers Three Laws Of Planetary Motion, The Law Of Orbits, The Law Of Areas, The Law Of Harmonics, Singularity,
Newton's Law Of Gravitation, Hubble Constant, The Roche Limit, Schwarzchild Radius, Universal Gravitational Constant "G",
Abberation, Absorption Lines, Albedo, Aphelion, Apogee, Apparent Motion, Asteroid Belt, Azimuth And Elevation, Balmer Series,
Black Body Radiation, Black Hole, Bradley's Aberration, Chromosphere, Cherenkov Radiation, Comet, Corona, Coronal Hole,
Coronal Mass Ejection, CME, Declination, Eccentricity, Ecliptic, Epicycle, Equatorial Axis, Hohmann Orbit, Hydrogen Spectrum,
Klemperer Rosette, Kuiper Belt, Lagrangian Points, Libration, Luminance, Luminosity, Mach's Formulation, Mean Anomaly, Multiplet,
Neutron Star, Nodal, Nodal Month, Nutation, Nutation Cycle, Oblateness, Obliquity, Oort Cloud, Orbit, Orbital Elements,
Orbital Inclination, Orbital Motion Anomaly, Orbital Period, Parallax, Perhelion, Perigee, Perturbation, PHA,
Photosphere, Plane Of The Ecliptic, Precession, Precession Cycle, Primary, Primordial Microwaves, Prominence,
Retrograde Motion, Right Ascension And Declination, Semimajor, Sidereal Day, Sidereal Month, Sidereal Time, Sodium Spectrum,
Solar Activity, Solar Cycle, Solar Energetic Particles, Solar Flare, Solar Wind, Spectral Line, Stellar Evolution, Supernova,
Synodic, Synodic Period, Synodic Month, Transit, True Anomaly, Urca Process, Van Allen Radiation Belt, Zeeman Effect,
Achromatic Refractor, Apochromatic Refractor, Newtonian Reflector, Schmidt-Cassegrain, Maksutov-Cassegrain,
Schmidt-Newtonian, Maksutov-Newtonian, Dobsonian, Ritchey-Chretien, Adaptive And Multi Mirror Optics,
Huygenian Eyepiece, Ramsden Eyepiece, Kellner Eyepiece, Orthoscopic Eyepiece, Plossl Eyepiece, Wide Field Eyepieces,
Erfle Eyepiece, Konig Eyepiece, Nagler Eyepiece
Thumbnail sketches of those men and women who though their efforts made astronomy
the science it is today, both fascinating and practicable to professional and amateur alike
While the data are public domain, the entire textual content and layout of the articles on this page are Copyright
© Brian Timmins 2008, et seq. All rights reserved. Should you wish to use any of it for personal research or educative
purposes, you may make one hard copy for your own use without further permission or charge. Teachers and educationalists
may make as many copies as they need for classroom/lecture purposes - an eMail to say you are doing this would be appreciated.
I have little doubt that… my researches have left out astronomers who ought to be included; the details of listed astronomers
may well be defficient; there may well be errors, both of inclusion and typographical. If any reader finds any such that need correction,
please do not hesitate to eMail me.
From Ancient Times to the Renaissance
Please note: This is currently a work in progress.
"Extended biographies" on this site are written by me. "Name, Biography" are biographies external to this site.
Eventually all Biographies on these pages will be mine. |
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- Ancient Astronomy
-
All the early civilisations - Chaldean, Sumerian, Assyrian, Babylonian Egyptian etc... studied, in the broadest possible
sense, astronomy and there are many tablets from these times showing their recorded observations. These were mostly used
for astrological-predictive purposes. From these ancient times the only known named astronomers were:
- Notable Ancient Middle-eastern Astronomers
- Tekhi
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An Egyptian astronomer priestess, dates totally unknown, but could have been 2000 BC ±500
years. She is credited with the invention of geometry, but nothing is really known about her. Indeed there having been a
minor Goddess called Tekhi, it is not known if the priestess was named after the goddess or with time, as was the
practice in ancient civilisations, she became known as a goddess.
- Sheshet
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Another Egyptian astronomer priestess, whose dates are also totally unknown. She is credited with
the creation of trigonometry. Other comments for Tekhi above, apply to her as well.
- En Hedu'anna
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Women have been involved in the study of the sky and all it contains for well over 4000 years. It began with the
priests and priestesses in Sumeria and Babylon. As early as 3000 BCE the temples in Sumer were complex structures that
directed every essential activity of life including trade, farming and crafts. The priests and priestesses established a
network of observatories to monitor the movements of the stars. The calendar they created is still used to date certain
religious events like Easter and Passover.
Around 2350 BC, one Sargon of Akkad - the founder of the Sargonian Dynasty in
ancient Babylon - appointed his daughter En Hedu'anna as his chief priestess of the Moon Goddess. Hers is the first
female name recorded in technical history. This was an incredibly powerful appointment, almost certainly second only to
Sargon himself. Her priestly name means "ornament of heaven" - her birth name is unknown. Only through the auspices of
the high priestess could a leader achieve a legitimate claim to rule.
Though we have no technical works we do have forty-two of her poems. One of these contains the following lines...
"The true woman who possesses exceeding wisdom,
She consults a tablet of lapis lazuli
She gives advice to all lands...
She measures off the heavens,
She places the measuring-cords on the earth."
It's pretty obvious from these lines that her studies related strongly to astronomical matters.
She was authorised to create observatories to record the movement of the planets and the stars. The uses to which these
observations were put, were of course, astrological in nature and used to forecast weather, rain crops etc. No matter
that this was not pure astronomy they were observations of the cycles of the heavens. A bas-relief, from which the image
is taken, of her is at the University Museum in Philadelphia.
- Aganice
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(Circa 1875 BC) Little is known of Aganice except that she was a member of the court of Pharaoh
Sestoris in Egypt. There are some claims that she was his daughter but she is not named as such in the Royal
family pyramid. She sought wisdom through natural philosophy and astrology. She studied globes and constellations in
order to predict future events. It is recorded that she computed the positions of the planets.
- Nakht
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An Egyptian scribe, with the title, "Astronomer of Amun" at the great temple of Karnak. during the
18th dynasty (Circa 1540-1307 BC). His job was to study the location of stars, the sun and the moon in order to schedule
festivals and cult rituals for the temple. Little is known about Nakht, except the fact that he had a wife called Tawy
and he was important enough to have his own tomb. Neither is it even clear which king he served under, though
indications are that it might have been Tuthmosis IV.
- Chinese Astronomers
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The Chinese have been observing the sky for thousands of years, making them the oldest civilization with a continuous
astronomical record. Their astronomers were required to correctly predict astronomical events, such as eclipses;
otherwise, they were executed. One of the earlist Chinese records is the first documented solar eclipse - over 4000
years ago in 2137 B.C. The first recording of any planetary grouping was made by the Chinese in 500 B.C. At about the
same time the Chinese made what is known as the Book of Silk. This is the earliest known atlas of comets, containing 29
comets, and is a collective history of about 300 years. They were called "broom stars" . The book was discovered in a
tomb in 1973. The astronomers noted the date, type, constellation in which it was first observed, motion, color,
apparent length, and duration in the sky of the comets. They were the first to discover that comet tails always point
away from the sun.The early Chinese astronomers compiled star charts, fragments of which have survived until today. The
astronomer Shih-Shen compiled a catalogue of stars containing descriptions of 122 constellations and 809 stars;
this pre-dated the catalogue of the Greek, Hipparchus. Even though early Chinese astronomers did achieve high
standards of astronomical knowledge, over a period of many centuries their astronomical calendars became inaccurate. The
Chinese did not resolve this problem until the Jesuits came to China in the 16th Century and were commissioned to
construct a more accurate calendar. The astronomical data compiled by the early Chinese astronomers is of great value as
no other records exist from around this period. For example, they recorded the appearance of comets in the years 989,
1066, 1145 and 1301. These apparitions are now known to be early appearances of Halley's Comet, although the Chinese
astronomers did not know that it was the same comet on each occasion. Arguably the most important observation that the
Chinese made was of the appearance of a supernova in 1054. During June 1054 the object was visible in the daytime. The
remnant of this supernova is the famous Crab Nebula in Taurus, one of the more interesting objects for observation.
- Notable Chinese Astronomers
- Gan De
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(Circa 4th century BC) Born in the State of Qi. Along with Shi Shen, he is the first in history to compile a star
catalogue. He made some of the first observations of Jupiter. He described the planet as "very large and bright". Gan De
is apocryphally reported to have seen one of the moons of Jupiter with his naked eye in 364 BC. It should be noted
that all four of the Galilean satellites of Jupiter technically visible to the unaided eye, but in practice they are
normally hidden by the glare of Jupiter. Possibly, by occluding Jupiter itself behind a vertical tree limb to prevent
the planet's glare from obscuring them, one or more of the Galilean moons might well be spotted in very favorable
conditions. Both Shi and Gan together made fairly accurate observations of the five major planets.
Gan De, Biography
- Shi Shen
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(Circa 4th century BC) Astronomer and contemporary of Gan De, born in the State of Wei.
Shi is credited with the cataloguing of 121 stars found in preserved texts. He also made the earliest surviving undated
record of sunspot observation, which is sometimes erroneously credited to Gan De. He assumed that these spots were eclipses
that began at the center of the sun and spread outward. Although he was wrong, he recognised the spots for what they were,
solar phenomena. His works included an 8-volume "Astronomy", a one-volume Celestial Map and a one-volume Star Catalogue of Shi.
- Jing Fang
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(78-37 BC). A music theorist, mathematician and astrologer born in present-day Puyang, Henan during the Han Dynasty.
He was a proponent of the 'radiating influence' theory. This stated that the light of the moon was merely the light
reflected from the sun, and that the celestial bodies were spherical. This wonderfully accurate theory was dismissed
by the philosopher Wang Chong (27-97 AD), yet embraced by the mathematician, inventor, and scientist Zhang Heng.
- Liu Xin
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(Died 23 AD)An astronomer, historian and minister to the Chinese usurper Wang Mang. during the Xin Dynasty.
The son of the Confucian scholar Liu Xiang, he created a new astronomical system, called "Triple Concordance".
He published this system in 8AD as section of his textbook. In it he provided the following periods:
- A synodic month of 29 43/81 days
- 235 synodic months add up to 19 years
Therefore his number of days in one year was 365 385/1539 days, which is only 11 minutes longer than the current value.
He also created a catalog of 1080 stars, where he used a scale of 6 magnitudes. He also calculated periods for the planets.
He has a crater on Mars named in his honor. In AD 4 he organized a national scientific congress attended by 1000 scholars.
- Zhang Heng
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(78-139 AD) Astronomer, mathematician, inventor, geographer, cartographer, artist, poet, statesman, and literary scholar
of the Eastern Han Dynasty. Best known for inventing the world's first water-powered armillary sphere to represent astronomical
observation. In addition to writing an extensive star catalogue, Zhang also posited theories about the moon and its relationship
to the sun, specifically the moon's sphericity, its illumination by reflecting sunlight, and solar and lunar eclipses.
He invented the seismograph and calculated the value of π. He understood the Earth was spherical, and that the Moon was
lit by the Sun, revolved around the Earth, and was eclipsed by Earth's shadow. He was able to explain why the day
shortened and lengthened.
Zhang Heng, Biography
- Li Fan
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(Circa 90 AD) An astronomer during the Han Dynasty. He recorded that the Moon does not move uniformally through
its phases by using the background stars as reference. He has a crater on Mars named in his honor.
- Gautama Siddha
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(Circa 8th century AD) A translator, astronomer, astrologer, and compiler of the Tang Dynasty known for his
major contribution to the Treatise on Astrology of the Kaiyuan Era. Born in Chang'an, and his family was originally from India,
according to an ancient plaque uncovered in 1977 in Xi'an. The only accomplishment recorded in any detail was his translation
of the Navagraha calendar into Chinese.
- Greek Astronomy
-
The first Greek astronomers were the philosophers, of whom many tried to have their ideas accepted by debating the
correctness previous philosophers. However, the works of the Greek philosophers Plato and Aristotle have
been preserved well, and both were highly esteemed in later epochs.
The Greeks were one of the most mathematically-orientated cultures of ancient times and this was in itself a problem.
As they were primaily mathematicians their observational astronomy left a lot to be desired. Eudoxus was the
first to formulate a mathematical model of planetary motion. Calippus added more. The most original ideas came
from Heraclides and Aristarchus, being the first to propose a heliocentric model for the Solar System.
During the second century BC, Hipparcus invented the epicyclic system, and although incorrect, the epicyclic
system could represent the motions of the planets and Moon to within an error of less than one arcmin.
Ptolemy, one of the greatest astronomers of ancient times, who lived in Alexandria during the time of the Roman
emperor Hadrian in the second century AD, favoured the epicyclic system of Hipparcus to the heliocentric system of
Aristarchus. Ptolemy refined the epicyclic system, and thus ever since, it has been known as The Ptolemaic System. It
should be mentioned that Ptolemy was the first observational astronomer as the term is understood in the modern sense...
his star catalogue was the most accurate at that time and for some time thereafter.
- Notable Ancient Greek Astronomers
- Hesiod Of Ascra
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(Circa 730 BC)
Son of Dios and Pycimede, Hesiod was a native of Cumae, in Asia Minor. The first Greek writer to name
himself in his works which are quoted by Athenaeus, Aristarchus, Eratosthenes, Ephorus, Pausanias,
Pliny, Plutarch, Praxiphanes, Suidas, Stobaeus and Strabo. He wrote many works the one of interest
here being "Astronomy" which was a Catalogue of stars. The only fragment which survives, courtesy
of Athenaeus, is commentary on the Pleiades.
Insufficient extra data to justify an Extended Astronomical Biography
- Thales of Miletus
-
(Circa 624-54y BC) Son of Examyes and Cleobuline. None of his works have survived but much has been gleaned for the writings of others.
He was founder of the Milesian school of philosphy and considered to be the first of the "Seven Sages".
He observed that the constellation called Ursa Major never dips below the horizon in Greece, but it does when viewed from Egypt.
It is said that he produced a work on navigation and that he predicted an eclipse of the Sun in 585 BC. The cycle of about
19 years for eclipses of the Moon was well known at this time but the cycle for eclipses of the Sun was harder to spot since
eclipses were visible at different places on Earth. Thales's prediction of the 585 BC eclipse was probably a guess based on the knowledge
that an eclipse around that time was possible. It is calculated to have been the eclipse of 28.5.585 BC Julian Calendar,
or 22.5.584 BC Gregorian Calendar. Said also to be the teacher of Animaxander.
Insufficient extra data to justify an Extended Astronomical Biography
- Pherekydes of Syros
-
(6th century BC) A teacher of Pythagoras - a thinker from the island of Syros. Little is known of his life. It has been claimed
that his father was called Babys. He is known for having constructed a sundial and a 'heliotropion' - supposedly the
first example of this type of instrument, which was a sort of advanced gnomon - which could be used to determine midday
and to calculate the length of the year and the geographical latitude. His writings included "On the seven sections of
the universe" in which he talked about the heaven of the fixed stars, the heaven of the 'wandering stars' (the planets),
sphere of the sun, sphere of the moon, sphere of the earth, and the underworld; also "Heptamychos" - a history of the
creation of the world. He also was able to predict lunar and solar eclipses.
Insufficient extra data to justify an Extended Astronomical Biography
- Theano Of Thurii
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(6th century BC) Daughter of a physician called Brontinus she became the wife and pupil of Pythagoras who was 36 years older than her.
She taught mathematics in his schools in Samos and Croton; and after his death became the head of his school. She is the
best-known female astronomer/cosmologist, and is cited by Athenaeus, Suidas, Diogenes Laërtius and Iamblichus. Her
writings include "Cosmology" and "Construction of the universe" wherein she posits that then universe is constructed in
simple mumeric distances based on the intervals of the musical scale. It is made up of ten concentric spheres
corresponding to the eight major known bodies plus a counter-Earth and the stars; all of which move in uniform circular
motions around a "central fire", except the fixed stars, which do not move. She was responsible for the concepts of the
golden mean, golden ratio, and golden rectangle.
Insufficient extra data to justify an Extended Astronomical Biography
- Anaximenes Of Lampsacus
-
(585-524 BC) Son of Eurystratus, he is generally thought of as the third of the great Milesian philosophers, after
Thales and Anaximander. Little is known about him other than he was a friend and student of Anaximander.
None of his works survive. His cosmology varied little from the general beliefs of the times except he
thought the earth was like a cork, floating on the surface of the air. He was the first to realise that
the moon shone by the reflected light of the sun, and thus was able to explain the eclipses of both bodies.
Insufficient extra data to justify an Extended Astronomical Biography
- Anaximander of Miletus
-
(Circa 560 BC)Son of Praxiades. According to Pliny the Elder he was born during the third year of the 42nd Olympiad (610 BC).
Pliny also says: "Anaximander Miletus traditur primus Olympiade quinquagesima octava...", indicating
he was alive during during the second year of the 58th Olympiad (547 BC-546 BC), and evidently died shortly afterwards at sixty-four
years of age. As with most of the
early ancient Greeks he was more of a philosopher than an astronomer. He was the first to conceive a mechanical model of the
world. In his model, the Earth floats very still in the centre of the infinite, not supported by anything. It remains "in the same
place because of its indifference", a point of view that Aristotle considered ingenious, but false. It's curious
shape is that of a cylinder with a height one-third of its diameter. The flat top forms the inhabited world, which is surrounded
by a circular oceanic mass.
Insufficient extra data to justify an Extended Astronomical Biography
- Cleostratus of Tenedos
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(Circa 536 BC, possibly 548-432 BC) It is thought he may have been a contemporary of the Chaldean astronomer Naburimannu.
According to remarks by Pliny the elder it might be evidenced that he introduced the zodiac and its associated solar
calendar to Greece from Babylonia. Very little is categorically known about him and most of the information about what
he did is gleaned from the writings of others. Gaius Julius Hyginus mentions: "Hos autem haedos Cleostratus Tenedius
dicitur primus inter sidera ostendisse...", and goes on to say that Cleostratus first pointed out the two stars
in Auriga called Haedi. Cleostratus crater, on the Moon, is named in his honour.
Insufficient extra data to justify an Extended Astronomical Biography
- Pythagoras of Samos
-
(Circa 530 BC) In astronomy Pythagoras taught that the Earth was a sphere at the centre of the Universe. He also recognised
that the orbit of the Moon was inclined to the equator of the Earth and he was one of the first to realise that Venus as an
evening star was the same planet as Venus as a morning star. He gave us the name "kosmos" for the universe. It is worth
noting that the antonym of cosmos is chaos.
Insufficient extra data to justify an Extended Astronomical Biography
- Heraclitus of Ephesus
-
(Circa 500 BC) Heraclitus had some fairly commonly held variations on cosmology based on the "four elements"
but some recently discovered writings seem to show that Heraclitus is concerned with technical questions of
astronomy, not only with general theory. He claimed that the Universe was 10,800 years old and was one of the
first people to refer to the universe as the kosmos.
(In 1766 Georges Buffon using the evidence of fossils showed that the Earth
is older than the 6000 years claimed by the Judeo-Christian religions).
Insufficient extra data to justify an Extended Astronomical Biography
- Timaeus Of Locri
-
(5th century BC)Timaeus was a scientific philosopher of the Pythagorean school who came from Locri, in southern Italy.
Plato is known to have studied with him while he was visiting Italy, and later wrote a dialogue between Timaeus and
Socrates. After the School in Croton was forced to close, he founded a Pythagorean School of his own. In his book
"Cosmology", he developed a theory of the creation of the universe wherein the gods created the earth out of matter
in the shape of a sphere and caused it to move in a circle.
Insufficient extra data to justify an Extended Astronomical Biography
- Diogenes of Apollonia
-
(Circa 5th century) He was a native of Apollonia, and the son of Apollothemis. It is almost impossible to determine
whether his birthplace - from which his name is derived - was the Apollonia of Crete or that of Phrygia (in modern
Turkey). He lived and worked for most of his life in Athens where it was reported that at times he was unpopular
enough, for his life to be at risk. A natural philosopher of high reputation in the Milesian tradition, he was a pupil
of Anaximenes, and a contemporary of Anaxagoras. Diogenes made astronomic observation from Crete and wrote several books
on Cosmology whence came his main astronomical claim to fame in that he was the first to suggest that meteorites come
from space - something which was subsequently forgotten for the next 2,000 years. Because of this claim, in his honour,
there is a class of meteorites called "diogenites".
Insufficient extra data to justify an Extended Astronomical Biography
- Parmenides of Elea
-
(Circa 470 BC) He was the founder of the Eleatic school of philosophy and there is no evidence of him being directly
interested in astronomy. However in his only known work (a poem which has survived only in fragmentary form he
postulated that the Earth's shape was spherical.
Insufficient extra data to justify an Extended Astronomical Biography
- Anaxagoras of Clazomenae
-
(500-428 BC) He taught that the moon shines with the light of the Sun, which he described as a hot red stone larger than
Peloponese, and thus explained the eclipses. He also agreed with the mathematicians, and held that the moon's
obscurations (phases), month by month, were due to its following the course of the sun by which it is illuminated, and
that the eclipses of the moon were caused by its falling within the shadow of the earth, which then comes beween the sun
and the moon, while the eclipses of the sun where due to the interposition of the moon. His observations of the
celestial bodies and the fall of meteorites led him to form new theories of the universal order. He attempted to give a
scientific account of eclipses, meteors, rainbows and the sun, which he described as a mass of blazing metal, larger
than the Peloponnese. The heavenly bodies, he asserted, were masses of stone torn from the earth and ignited by rapid
rotation. However, these theories brought him into collision with the popular faith; Anaxagoras' views on such things as
heavenly bodies were considered "dangerous".
Insufficient extra data to justify an Extended Astronomical Biography
- Leucippus of Miletus
-
(Circa 480-420 BC) Leucippus of Miletus carried on the scientific philosophy which had begun to become associated with
Miletus. We know little of his life but it is thought that he founded the School at Abdera jointly with Democritus.
Today the town is in Greece and is called Avdhira. At the time that Leucippus would have lived in Abdera it was a
prosperous town which politically was a member of the Delian League. Together he and Democritus are considered to be
the joint founders of atomic theory. He said that the world consisted in the void and atoms, which are imperceptible
individual particles that differ only in size, shape, and position. That these particles were imperceptible meant they
met Parmenides' objection to the Pythagorean's geometric points and, since they alone were unchanging, change could be
explained as mere sense impressions. According to Diogenes Laertius, the cosmology put forward by Leucippus in The Great
World System is a creation of worlds by agglomerations of atoms by chance collisions. There is then differentiation with
the smaller atoms being sent off into the infinity of space while the rest form into a spherical structure with the
larger atoms at the centre and the smaller atoms further away from the centre. From the treatise On the Mind we have
the only quotation of the words of Leucippus which have survived. In this work he writes:
"Nothing happens in vain, but everything from reason and of necessity."
Insufficient extra data to justify an Extended Astronomical Biography
- Philolaus of Croton
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(480-385 BC) He was from southern Italy and was the precursor of Copernicus in moving the
earth from the center of the cosmos and making it a planet, but in Philolaus' system it does not orbit the sun but
rather the central fire. Some scholars regard the astronomical system as a significant attempt to try to explain the
phenomena, but others see it as primarily of mythic and religious significance. Philolaus is the first to incorporate
all five planets commonly known in antiquity into an astronomical scheme in the correct order, which indicates that he
was aware of the most up-to-date astronomical data.
Extended Biography
- Democritus of Abdera
-
(460-370 BC)A hugely influential scientist/philosopher, arguably the equal of Aristotle. Son of either Hegesistratus or Athenocritus,
he was born in 460 BC in Abdera, Thrace. He studied under Leucippus and then travelled widely throughout most of
the then known world, possibly as far as India. Finally he returned to Abdera and founded a highly thought ofschool.
His most famous treatise formulated the beginnings of atomic theory wherein he described atoms as being
"imperceptibly small" and "indivisable". He also produced works on Astronomy and Cosmology as well as a wide
variety of books (70+) on other scientific subjects.
Extended Biography
- Oenopides of Chios
-
(Circa 450 BC) Mathematician and astronomer.
He was born on the island of Chios(nowadays Khios), but mostly worked in Athens. His main accomplishment as an astronomer was
his determination of the angle between the plane of the celestial equator and the zodiac, this being the yearly
path of the sun in the sky, which he calculated as to be 24°. In effect this amounted to measuring the
inclination of the earth axis. Oenopides's result remained the standard value for two centuries, until
Eratosthenes measured it with greater precision.
Extended Biography
- Meton of Athens
-
(Circa 440 BC) He was a mathematician, astronomer, geometer, and engineer and discovered
that 235 lunar months made up just about 19 years. This became known as the Metonic cycle and was used as the basis for
the Greek calendar until 46 BC and the introduction of the Julian calendar. He was one of the first Greek astronomers
to make accurate astronomical observations.
Extended Biography
- Euctemon of Athens
-
(Circa 432 BC) - an Athenian astronomer. He was a pupil of Meton and worked closely with
him, but little is known of his work apart from his partnership with Meton which is mentioned by Ptolemy.
With Meton, he made a series of observations of the solstices (the points at which the sun is at greatest distance from
the equator) in order to determine the length of the tropical year. Both Geminus and Ptolemy quote him as a source on the
rising and setting of the stars. The lunar crater Euctemon is named after him. This was the most significant of all the
early attempts to provide some commensurability between a religious lunar calendar and the tropical year.
Insufficient extra data to justify an Extended Astronomical Biography
- Philip of Opus
-
(Circa 415 BC) He was a astronomer and mathematician and a member of the Academy during Plato's
lifetime. It is thought that he was the editor of Plato's Laws and even that he actually wrote the thirteenth book of
the Laws, called the "Epinomis", himself.
Because he is identified in a 12th century Byzantine Greek encyclopaedia called the "Souda", as an
astronomer, it is generally accepted that Philip of Opus is the same person as Philip of Medma, also an astronomer and
mathematician and a disciple of Plato. Philip of Medma is mentioned by several ancient writers such as Vitruvius, Pliny
the Elder, Plutarch, Proclus, and Alexander of Aphrodisias. His astronomical observations were made in the Peloponnese
and in Locris, and were used by the astronomers Hipparchus, Geminus of Rhodes, and Ptolemy.
Insufficient extra data to justify an Extended Astronomical Biography
- Xenocrates Of Chalcedon
-
(396-314 BC) A philosopher, mathematician, and leader of The Academy from 339 to 314 BC. He followed the teachings of
Plato, which he attempted to define more closely, often with mathematical elements. He held that mathematical objects
and the Platonic Ideas are identical, unlike Plato who distinguished them. He was an early advocate of the atomic theory
of matter and gave particular importance to mathematics, especially a theory of numbers and wrote many treatises on
both maths and astronomy.
Extended Biography
- Aristotle Of Stagira
-
(384-322 BC)Aristotle was born in Stagirus on the Chalcidic peninsula of northern Greece. His father was Nicomachus, a medical
doctor, while his mother was named Phaestis. Nicomachus was certainly living in Chalcidice when Aristotle was born and
he had probably been born in that region. Aristotle's mother, Phaestis, came from Chalcis in Euboea and her family owned
property there. In 367 BC Aristotle became a student at Plato's Academy in Athens. When Aristotle arrived in Athens, the
Academy was being run by Eudoxus of Cnidos in Plato's absence. Speusippus, Plato's nephew, was also teaching at the
Academy as was Xenocrates of Chalcedon. After being a student, Aristotle soon became a teacher at the Academy and he was
to remain there for twenty years. We know little regarding what Aristotle taught at the Academy. In 335 BC Aristotle had
founded his own school the Lyceum in Athens where according to a tradition Aristotle in these same years lectured - not
once, but two or three times, in almost every subject - on logic, physics, astronomy, meteorology, zoology, metaphysics,
theology, psychology, politics, economics, ethics, rhetoric, poetics. Little or none of his actual works survive except
as fragments quoted in other scholars works. However probably most if not all of his lecture notes were published in
about 60 BC by Andronicus of Rhodes (the last leader of the Lyceum), almost certainly expanded and annotated by his
successors. He was not primarily a scientist but made important contributions by systematising deductive logic. His only
known contributions to astronomy were in the study of comets.
Insufficient extra data to justify an Extended Astronomical Biography
- Eudoxus of Cnidus
-
(408 - 355 BC) Eudoxus of Cnidus was the son of Aischines. As to his teachers, we know
that he travelled to Tarentum, now in Italy, where he studied with Archytas who was a follower of Pythagoras. After
spending in Athens, he spent over a year in Egypt where he studied astronomy with the priests at Heliopolis. At this
time Eudoxus made astronomical observations from an observatory which was situated between Heliopolis and Cercesura.
Eudoxus returned to his native Cnidus and there was acclaimed by the people who put him into an important role in the
legislature. However he continued his scholarly work, writing books and lecturing on theology, astronomy and
meteorology. He had built an observatory on Cnidus and we know that from there he observed the star Canopus. The
observations made at his observatory in Cnidus, as well as those made at the observatory near Heliopolis, formed the
basis of two books referred to by Hipparchus. These works were the Mirror and the Phaenomena which are thought by some
scholars to be revisions of the same work. Hipparchus tells us that the works concerned the rising and setting of the
constellations but unfortunately these books, as all the works of Eudoxus, have been lost. It should be noted that
Eudoxus was primarily a mathematician and from the comments of others this is where his main research was located.
Extended Biography
- Hicetas of Syracuse
-
(Circa 400-335 BC) was a Greek philosopher of the Pythagorean School. He was born in Syracuse. Like
his fellow Pythagorean Ecphantus and the Academic Heraclides Ponticus, he believed that the daily movement of permanent
stars was caused by the rotation of the Earth around its axis. This trio of philosophers is reported by both Cicero and
Calcidius to have thought that Venus and Mercury revolve around the Sun, not the Earth.
Insufficient extra data to justify an Extended Astronomical Biography
- Heraclides of Pontus
-
(387-312 BC) His father, Euthyphron, was a wealthy nobleman in Heraclea Pontica. Heraclides has been famous
for a long time as being the first to suggest the heliocentric model of the solar system. However this has been shown to
be due to a misunderstanding of his writings. We know a bit about Heraclides' life. He attended the Academy in Athens
and in 260 BC was left in charge of it during Plato's third visit to Sicily. When describing the circle of Venus as
well as that of the sun, and giving the two circles one centre and one mean motion, showed how Venus is sometimes
above, sometimes below the sun. This has been interpreted by many commentators and historians but none of whom can agree
on its precise meaning. He is the first known to have believed that the earth rotates once per day and certainly
deserves full credit for it.
Extended Biography
- Callippus of Cyzicus
-
(Circa 370-300 BC) He was born at Cyzicus, and studied under Eudoxus of Cnidus at the Academy of Plato. He also worked
with Aristotle at the Lyceum He observed the movements of the planets and attempted to use Eudoxus' scheme of connected
spheres to account for their movements by extending the number of spheres used. He made careful measurements of the
lengths of the seasons, and starting with the spring equinox he found them to be unequal. He also followed up on the
work done by Meton of Athens to measure the length of the year and construct an accurate lunisolar calendar. The Metonic
cycle has 19 tropical years and 235 synodic months in 6940 days. The Callippic cycle synchronized the lunar and solar
years better than the Metonic cycle, by dropping 1 day after 4 Metonic cycles, a duration of 76 years, making the
Callippic 19 year cycle equal to 6439 3/4 days, or exactly 365 1/4 days per year.
Extended Biography
- Autolycus of Pitane
-
(Circa 360-290 BC) Autolycus of Pitane, Astronomer, mathematician, and geographer. Pitane was a
town of Aeolis within Western Anatolia. In astronomy, Autolycus studied the relationship between the rising and the
setting of the celestial bodies. He wrote that "any star which rises and sets always rises and sets at the same point
in the horizon." He relied heavily on Eudoxus' astronomy and was a strong supporter of Eudoxus' theory of homocentric
spheres.
Extended Biography
- Eudemus Of Rhodes
-
Born on Rhodes and we know that he had a brother called Boethus. Nothing is known of the rest of his family or early life.
However along with Theophrastus of Lesbos, he was one of Aristotle's most brilliant pupils and both of them were usually
referred to as Aristotle's companions rather than disciples. It would seem that Theophrastus was the more original
thinker of the two and Eudemus' main skill lay in systematizing and correlating Aristotle's philosophical works and
presenting his master's works in a manner easy to teach and understand. This has led to him being considered the first
scientific historian. Shortly before his death Aristotle designated Theophrastus to be his successor as head of his
Peripatetic School. At this point Eudemus returned to Rhodes, where he founded his own school, continued his own
research, and carried on editing Aristotle's work. His History of Astronomy was heavily used by later writers.
A great deal of historical information has thus survived in the works of others. Specifically:
- Thales' eclipse prediction
- Eudoxus' system of concentric spheres
- The cycle of the great year
- Anaximander's thoughts on the earth being a heavenly body moving about the middle of the universe
- The discovery by Anaximenes that the moon reflects the light of the sun and the explanation of lunar eclipses
- The inequality of the times between the solstices and the equinoxes
Insufficient extra data to justify an Extended Astronomical Biography
- Epicurus Of Samos
-
(341-271 BC)Born in Samos, son of Neocles and Chaerestrate, both Athenians. He studied first with Pamphilus, a Platonist, and
later on the neighbouring island of Teos with Nausiphanes: This was his first introduction to the theories of
Democritus. After two years of military service he went to Colophon, and then on to Mytilene and Lampsacus. In all
these places he taught, and gradually developed his pwn philosophical system. Then he returned to Athens, where he
founded his famous school and laid the foundations of the Epicurean/Hedonistic system. He also made a particular study
of astronomy and meteorology and supported the atomic theory of Leucippus and Democritus, formulating the view that
everything in nature comes from the movement of the atom in a void. Most of his works - over 300 - have been lost
and like others he survives mainly by being quoted by such luminaries as Suidas, Diogenes Laërtius, Cicero,
Sextus Empiricus, Apollodorus, Diotimus, Posidonius, Stobaeus, Sotion and Dionysus of Halicarnassus.
Insufficient extra data to justify an Extended Astronomical Biography
- Timocharis of Alexandria
-
(320-260 BC) Born in Alexandria, he was a contemporary of Euclid and worked with Aristarchus and Aristyllus.
With the help of Aristillus, he created the first star catalogue
in the Western world. Over 150 years later, Hipparchus would compare his own star catalogue to Timocharis' and discover
that the longitude of the stars had changed over time, which led him to determine the first value of the precession of
the equinoxes. The Timocharis crater on the Moon is named after him. He made the third recorded mention of Mercury.
Insufficient extra data to justify an Extended Astronomical Biography
- Aratus Of Soli
-
(Circa 315-240 BC) Born in Soli in Cilicia, he was a contemporary of Callimachus and Theocritus. He is also known to
have studied with Menecrates in Ephesus and Philitas in Cos. His work that interests us most is "Phaenomena"
(Appearances), the first half of which is a verse setting of a lost work of the same name by Eudoxus of Cnidus, which
describes the constellations and other celestial phenomena. The second half is chiefly about weather lore.
Though he was not an astronomer per se the Aratus crater on the Moon was named in his honour.
Insufficient extra data to justify an Extended Astronomical Biography
- Aristarchus of Samos
-
(Circa 310-230 BC) Aristarchus of Samos was an astronomer and mathematician.
He was the first person to present an explicit argument for a heliocentric model of the solar system,
placing the Sun, not the Earth, at the center of the known universe (hence he is sometimes known as the "Greek
Copernicus"). He was influenced by the Pythagorean Philolaus of Kroton, but in contrast to Philolaus he had both
identified the central fire with the Sun, as well as putting other planets in correct order from the Sun. His
astronomical ideas were rejected in favor of the geocentric theories of Aristotle and Ptolemy until they were
successfully revived by Copernicus and extensively developed and built upon by Kepler and Isaac Newton nearly 2000 years
later. The Aristarchus crater on the Moon was named in his honour.
Extended Biography
- Aristillus of Alexandria
-
(280 BC) He created the first star catalogue in approximately 300 BC, with the help
of Timocharis. He worked in the Great Library of Alexandria. The lunar crater Aristillus is named after him.
Insufficient extra data to justify an Extended Astronomical Biography
- Conon of Samos
-
(Circa 280-220 BC)Astronomer and mathematician, he was born on Samos, Ionia, and possibly died in Alexandria. He named
the constellation Coma Berenices ("Berenice's Hair") after Ptolemy's wife Berenice II. However, in Ptolemy's Almagest,
Coma Berenices is not listed as a distinct constellation, but Ptolemy does attribute several seasonal indications
(parapegma) to Conon. In astronomy, Conon's main contribution was his seven books "De astrologia" - now lost. These
included observations on solar eclipses. He is cited by Seneca as being "a careful observer" and Catullus - "he
discerned all the lights of the vast universe". Conon was a friend of the mathematician Archimedes whom he probably met
at Alexandria, and it is claimed that "Archimedes Spiral" was actually first defined by Conon, though finally proven by
Archimedes. That he and Archimedes were very good friends and colleagues, with a high regard for each other, there is
little doubt. Conon's work on conic sections became a basis for the fourth book of Conics of Apollonius of Perga.
Insufficient extra data to justify an Extended Astronomical Biography
- Eratosthenes of Cyrene
-
(276-194 BC) Eratosthenes was born in Cyrene which is now Shahhat in Libya in North Africa. His teachers included the
scholar Lysanias of Cyrene, the philosopher Ariston of Chios who had studied under Zeno, and the scholar Callimachus of.
He then moved to Athens for some years. Then, in about 240 BC, Eratosthenes became the third librarian at the famous
library of Alexandria which was said to have contained hundreds of thousands of papyrus and vellum scrolls. Eratosthenes
was primarily a mathematician and is remembered for his prime number sieve, the 'Sieve of Eratosthenes' which, in
modified form, is still an important tool in number theory research. However, Eratosthenes will always be remembered for
his incredibly accurate measurement of the circumference of the Earth. His actual work has been lost but some details of
these calculations appear in works by other authors such as Cleomedes, Theon of Smyrna and Strabo. He compared the noon
shadow at midsummer between Syene (now Aswan) and Alexandria and assumed that the sun was so far away that its rays were
essentially parallel. Then knowing the distance between Syene and Alexandria, he gave the length of the circumference of
the Earth as 250,000 stadia. There has been much debate on the actual size of a stadium but his result is very accurate
if the figure of 157.2 metres as given by Pliny. He also measured the distance to the sun as 804,000,000 stadia and the
distance to the Moon as 780,000 stadia. He computed these distances using data obtained during lunar eclipses. Ptolemy
records that Eratosthenes measured the tilt of the Earth's axis with great accuracy obtaining the value of 11/83 of
180°, namely 23° 51' 15". He is also said to have compiled a star catalogue containing 675 stars. Eratosthenes
made many other major contributions to the progress of science. He worked out a calendar that included leap years, and
he laid the foundations of a systematic chronography of the world when he tried to give the dates of literary and
political events from the time of the siege of Troy. Eratosthenes made major contributions to geography. He sketched,
quite accurately, the route of the Nile to Khartoum, showing the two Ethiopian tributaries. He also suggested that lakes
were the source of the river.
Insufficient extra data to justify an Extended Astronomical Biography
- Apollonius of Perga
-
(Circa 262-190 BC) He was primarily a mathematician of the Alexandrian school, noted for his
writings on conic sections. His innovative methodology and terminology, especially in the field of conics, influenced many later
scholars including Ptolemy, Francesco Maurolico, Isaac Newton, and René Descartes. It was Apollonius who gave the ellipse,
parabola, and hyperbola, the names by which we know them today. The hypothesis of eccentric orbits, or equivalently, deferent and
epicycles, to explain the apparent motion of the planets and the varying speed of the Moon, are also attributed to him. He also
developed the lunar theory, for which he is said to have been called Epsilon. The Apollonius crater on the Moon was named in his honor.
Insufficient extra data to justify an Extended Astronomical Biography
- Aglaonike of Thessaly
-
(2nd century BC) She is frequently, but erroneously, cited as the first female astronomer - see
En Hedu'anna, but certainly was the first female astronomer in ancient Greece. She can be
regarded as having mastered the art of predicting eclipses. This ability to forecast a lunar eclipse would be possible
for anyone of that time to do who was familiar with the periods of the full moon and the cycles of eclipses (the Metonic
cycle). The superstitions of the time allowed a person with such knowledge to control people through their fear of the
unknown. She was one of those women who were known as the witches of Thessaly (1st through 3rd centuries BC). It is
likely Aglaonice was regarded as a sorceress by her contemporaries for her skills. She is mentioned in the writings of
Plato as a sorceress. A crater on the planet Venus is named for her.
Insufficient extra data to justify an Extended Astronomical Biography
- Hipparchus of Rhodes
-
(Circa 190-120 BC) Hipparchus was born in Nicaea in Bithynia, but spent much of his life in
Rhodes. Works by Hipparchus (now lost) included an astronomical calendar, books on optics and arithmetic. Ptolemy's
writings are the source of most of what we know about Hipparchus. In his own astronomical work, Ptolemy made extensive
use of the work of Hipparchus One of his contributions appears to have been the incorporation of numerical data based on
observations into the various geometrical models developed to account for the astronomical motions. His recorded
observations span the years 147 to 127 BC. He made extensive observations of star positions, and is credited by some
with the production of the first known catalogue of stars. He covered a wide variety of astronomical questions,
including the length of the year, the determination of lunar distance and the computation of lunar and solar eclipses
developing theories for the motions of the Sun and Moon. He did not establish theories for the five planets, but he did
compile the planetary observations to which he had access into a more useful arrangement, and showed that these
observations did not agree with the models the astronomers of that time'. Even the most casual criticism of the ancient
astronomers cannot fail to name Hipparchus one of the greatest astronomers.
Extended Biography
- Theodosius of Bithynia
-
(160-90 BC) He was the author of "Sphaerics", a book on the geometry of the sphere,
written to provide a mathematical background for astronomy. Two other works by Theodosius have survived. These are "On
Habitations" and "On Days And Nights" Both are concerned with the differing lengths of days and night in differing
lattitudes of the world. Theodosius is also reported to have invented a universal sundial suitable for all regions but
nothing has survived.
Theodosius of Bithynia, Biography
- Posidonius of Rhodes
-
(Circa 135-51 BC)Stoic philosopher and astronomer native to Apamea, Syria. He was acclaimed as
the greatest polymath of his age. None of his vast body of work can be read in its entirety today as it exists only in
fragments. A very few fragments of his writings on astronomy survive through Cleomedes, On the "Circular Motions of the
Celestial Bodies", the first chapter of Cleomedes second book would seem to have been copied from Posidonius. He
proposed that the Sun emanated a vital force which permeated the world. He measured the distance and size of the sun
and moon. Posidonius constructed an orrery, possibly similar to the Antikythera mechanism.
Posidonius of Rhodes, Biography
- Andronicus of Cyrrhus
-
Son of Hermias, was a Greek astronomer who flourished about 100 BC. He built a horologium at Athens,
the so-called Tower of the Winds, a considerable portion of which still exists. It is octagonal, with figures carved on each side,
representing the eight principal winds. In antiquity a bronze figure of Triton on the summit, with a rod in his hand, turned round by
the wind, pointed to the quarter from which it blew. This is the source of the custom of placing weathercocks on steeples.
- Sosigenes of Alexandria
-
(Circa 1st century BC) Sosigenes' astronomical writings, including Revolving
Spheres, have all been lost, except for isolated fragments. One notable fragment mentions Sosigenes' belief that Mercury
revolved around the Sun. However it is as a result of being consulted by Julius Caesar that we have the format of our
modern calendar. He told Caesar to boldly extend 46 BC to 445 days to get the calendar back in sync with the seasons, and
then to start afresh in 45 BC with the 365¼-day year. The upshot of his advice is the leap year and our February
29th
- Cleomedes
-
(Circa 10 BC - circa 70 AD)The book for which Cleomedes is known is a basic astronomy textbook,
in which he extensive amount of time criticizing the (admittedly fallacious) scientific ideas of the Epicureans. His book is criticized by most modern astronomers
as being poorly written, its main value being for the preservation of much of Posidonius' writings on astronomy, none of which
have survived. Cleomedes is accurate in some of his observations on lunar eclipses, especially his conjecture that the shadow on the
Moon suggests a spherical Earth.
Cleomedes, Biography
- Geminus
-
(10 BC - 60 AD) Geminus wrote a number of astronomy texts, including "Isagoge" or "Introduction to
Astronomy" based on the work of Hipparchus which we referred to above. He wrote an historical account of earlier
astronomical theories including those of Callippus and the Chaldeans. He made a significant comment on the stars, but
the main part of his works contains little mathematical astronomy. He describes the main constellations, the variation
of the length of night and day at different latitudes, the rising of the signs of the zodiac, and the length of the
lunar month. The phases of the moon, solar and lunar eclipsesand the motion of the planets are discussed and
explained
Geminus, Biography
- Theodosius Of Tripolis(1st century AD)
-
To be added soon
Insufficient extra data to justify an Extended Astronomical Biography
- Menelaus Of Alexandria(1st century AD)
-
To be added soon
Insufficient extra data to justify an Extended Astronomical Biography
- Agrippa
-
(Died 92 AD) The only thing that is known about him was an astronomical observation that he made in 92 AD.
In the twelfth year of the reign of Domitian, on the seventh day of the Bithynian month Metrous, Agrippa observed the occultation
of a part of the Pleiades by the southernmost part of the Moon. The reason for Agrippa's observation was almost certainly to check the
precession of the equinoxes, which had been discovered by Hipparchus. The lunar crater Agrippa is named after him.
- Claudius Ptolemy
-
(86-185 AD) Despite his fame today, nothing reliable is known of Claudius Ptolemy's life that
cannot be deduced from his surviving works. Only a few brief and unsupported biographical statements are made by much
later sources. 'Claudius' suggests he held Roman citizenship, 'Ptolemy' that he was of Greek descent and lived in
Egypt. Hi astronomical observations that he listed as having made himself cover the period 127-141 AD, from which it
may be inferred that he was active in the first and into the second half of the second century AD. He was one of the
most influential Greek astronomers and geographers of his time being the proposer of the geocentric theory in a form
that prevailed for 1400 years. Of all the ancient Greek mathematicians, his work has created more debate than any other.
Ptolemy's most important work is the "Almagest" which is a treatise in thirteen books, giving in detail the mathematical
theory of the motions of the Sun, Moon, and planets. These theories were accepted as 'deus ex machina' until Copernicus
presented his heliocentric theory in the De revolutionibus of 1543. Toomer sums up the Almagest as follows: "As a
didactic work the "Almagest" is a masterpiece of clarity and method, superior to any ancient scientific textbook and
with few peers from any period. But it is much more than that. Far from being a mere 'systemisation' of earlier Greek
astronomy, as it is sometimes described, it is in many respects an original work. In a book entitled Analemma he
discussed methods of finding the angles need to construct a sundial which involves the projection of points on the
celestial sphere. Another work on Optics is in five books and in it Ptolemy studies colour, reflection, refraction, and
mirrors of various shapes.
Claudius Ptolemy, Biography
- Adrastus Of Aphrodisias(2nd Century AD)
-
To be added soon
Insufficient extra data to justify an Extended Astronomical Biography
- Hypsicles Of Alexandria(2nd century AD)
-
To be added soon
Insufficient extra data to justify an Extended Astronomical Biography
- Sporus of Nicaea
-
(240-300 AD) Sporus was taught by Philon of Gadara, and we know of him through the writins
of Pappus's and Eutocius. He was mainly a mathematician, and produced some justifiable critiques concerning the attempts
of other philosophers to square the circle. He also wrote on the size of the Sun and on comets.
Sporus of Nicaea, Biography
- Theon of Alexandria
-
(335-405 AD) Theon of Alexandria worked in Alexandria as a teacher of mathematics and
astronomy. We know from his own writings that he observed a solar eclipse on 16 June 364 at Alexandria and a lunar
eclipse, again in Alexandria, on 25 November 364. Theon was a competent but unoriginal mathematician.
However, Theon amplified Euclid's text whenever he thought that an argument was overly brief, sometimes adding
propositions successfully making the text easier to read by beginners. He also produced commentaries
on other works of Euclid. Certainly he produced a commentary on Euclid's Optics and on his Data. He also wrote
extensive commentaries on the astronomical works of Ptolemy, both on the Almagest and the Handy tables. His
daughter Hypatia assisted him in the commentary on the Almagest and this is Theon's most major piece of work.
Theon of Alexandria, Biography
Proclus Of Lycia (Diadochus)(411-486 AD)
To be added soon
Insufficient extra data to justify an Extended Astronomical Biography
Heliodorus Of Alexandria(Late 5th century AD, d.509)
To be added soon
Insufficient extra data to justify an Extended Astronomical Biography
- Islamic Astronomy
-
While Europe was wallowing in the intellectual despair of what are known as the Dark Ages, though if truth be known they
were not quite as bad as some made them out to be. There is, in your authors opinion a dichotomy concerning this
epoch. That the Roman Catholic Church kept alive many of the skills and a lot of the knowledge that was directly useful
so far as the church was concerned cannot be argued, but they were also guilty of the greatest historical crimes ever
perpetrated in their destruction of other beliefs, the supressing of knowledge counter to their vested interests and the
character assassination and murder (under the guise of execution for heresy) of anyone who stood in their way. This was
the time when the Muslims became the torchbearers of knowledge in a very dark world, creating a great Islamic
civilization, driven by inquiry and invention, which was the envy of the rest of the world for many hundreds of years.
Not, your author hastens to add, that the Islamic faith was without its faults. It is a sad fact of human history that
the worst excesses of the human race have been performed because of religious intolerance of one sort or another. There
are few faiths that do not have a murky past, in fact I can only think of one that does not...Buddhism. Having studied
the Greek and Hindu mathematical-astronomers, they translated and largely surpassed most of their works. One of their
greatest triumhs was the adoption of the Hindu concept of "zero". So successful were they that it was not until the late
twentieth century that it was realised (by most of the western world) that the so-called "Arabic Numerals" were, in fact
Hindu. I personally can remember being taught at school, in the 1950s and '60s, about the Arabic invention of our
modern day numerals. When understanding Arabic names it is useful to understand that "Al" is equivalent to "the" and
more or less similar in use to the Scottish use when referring to a clan chief as, for example "The MacDonald". "Ibn" is
directly equivalent to the Scottish "Mac" or the Irish "O" as in O'Neil, meaning "son of". Finally "Abu" means "father
of".
- Notable Islamic Astronomers
- Al Balkhi
- (787-886 AD)
Ja'far ibn Muhammad Abu Ma'shar al-Balkhi , also known as al-Falaki or Albumasar was a Persian (Tajik) mathematician,
astronomer, astrologer and Islamic philosopher. Many of his works were translated into Latin and were well known in
amongst many European astrologers, astronomers, and mathematicians during the European Middle Ages. He has been credited
as the first astronomer to define astrological ages - the Age of Pisces, the Age of Aquarius, etc. - on the basis of the
precession of the equinoxes through the zodiac. He developed a planetary model which has been interpreted as a
heliocentric model. This is due to his orbital revolutions of the planets being given as heliocentric revolutions rather
than geocentric revolutions, and the only known planetary theory in which this occurs is in the heliocentric theory. His
work on planetary theory has not survived, but his astronomical data was later recorded by al-Hashimi and al-Biruni.
- Al-Khwarizmi
- (Circa 790-840 AD)
Abu Ja'far Muhammad ibn Musa Al-Khwarizmi was an Islamic mathematician and astronomer who worked on Hindu-Arabic
numerals and was among the first to use the zero. The word algorithm derives from his name, and his most famous work
"Hisab al-jabr w'al-muqabala" gave us the word algebra and can be considered as the first book to be written on this
subject. Al-Khwarizmi worked under the patronage of Caliph Al-Mamun at the House of Wisdom in Baghdad. His tasks there
included the translation of Greek scientific manuscripts, algebra, geometry and astronomy. Al-Khwarizmi also wrote a
treatise on Hindu-Arabic numerals. The Arabic text is lost but a Latin translation, Algoritmi de numero Indorum in
English Al-Khwarizmi on the Hindu Art of Reckoning gave rise to the word algorithm deriving from his name in the title.
Another important work by al-Khwarizmi was his work Sindhind zij on astronomy. The work is based on an Indian
astronomical text on which al-Khwarizmi based his treatise was one which had been given to the court in Baghdad around
770 as a gift from an Indian political mission. The main topics covered by al-Khwarizmi in the Sindhind zij are
calendars; calculating true positions of the sun, moon and planets, tables of sines and tangents; spherical astronomy;
astrological tables; parallax and eclipse calculations; and visibility of the moon. Although his astronomical work is
based on that of the Indians, and most of the values from which he constructed his tables came from Hindu astronomers,
he must have been influenced by Ptolemy's work too.
Al-Khwarizmi, Biography
- Thabit Ibn Qurrah
- (836-901 AD)
Thabit ibn Qurrah ibn Marwan al-Harrani, known in the West as Thebit, is known for his work on mechanics, astronomy,
pure mathematics and geometry. Thabit added the ninth sphere to Ptolemic astronomy. Some early investigators criticized
his work on 'Trepidation of Equinoxes' and several centuries later Tycho Brahe (1546-1601) improved upon his work.
Thabit analyzed several problems on the movements of sun and moon and wrote treatises on sundials. Beer and Madler in
their famous work Der Mond (1837) mention a surface feature of the moon after Thabit (Thebit). It is a prominent
circular plain thirty miles in diameter in Section No. 8. The intrusion of a small circular plain has disfigured its
circular wall. A small crater has thrust itself in on the eastern side of this plain. Thabit's books on mathematics,
astronomy and medicine have survived.
Thabit Ibn Qurrah, Biography
- Abu Abdullah Al-Battani
- (Circa 868-929 AD)
Known in the West as Albategnius, he was an astronomer and mathematician. Was`responsible for working
out an extremely accurate length of the year as used in the Gregorian calendar. He determined the time of the equinoxes
and calculated the earth's obliquity i.e. the inclination of the earth's equator to its orbital plane.
He was the author of the Sabian tables (al-Zij al-Sabi), a work which had huge impact on succeeding astronomers,
Muslim and Christian alike. These improved tables of the orbits of the sun and the moon showed that the direction
of the sun's eccentric as recorded by Ptolemy was changing. He also worked on the prediction of eclipses,
and the phenomenon of parallax, carrying us to the verge of relativity and the space age.
Abu Abdullah Al-Battani, Biography
- Al-Farghani Abu al-Abbas
- (ca. 860 AD) Known in the West as Al-Fraganus
Abu'l-Abbas Ahmad ibn Muhammad ibn Kathir al-Farghani, born in Farghana, Transoxiana, was one of the most distinguished
of Islamic astronomers. He wrote "Elements of Astronomy" (Kitab fi al-Harakat al-Samawiya wa Jawami Ilm al-Nujum i.e.
the book on celestial motion and thorough science of the stars), which was translated into Latin in the 12th century and
exerted great influence upon European astronomy. He accepted Ptolemy's theory and value of the precession, but thought
that it affected not only the stars but also the planets. He determined the diameter of the earth to be 6,500 miles, and
found the greatest distances and also the diameters of the planets. Al-Farghani's activities extended to engineering,
and the writing of "The Book of Chapters, a summary of the Almagest" and "Book on the Construction of Sun-dials" (Kitab
'Amal al-Rukhamat), wherein he explained the mathematical theory behind the instrument and corrected faulty geometrical
constructions of the central disc that were current then. The Jawami, or 'The Elements' as we shall call it, was Al-
Farghani's best-known and most influential work. References to it by medieval writers are many, and there is no doubt
that it was greatly responsible for spreading knowledge of Ptolemaic astronomy.
- Abd-al Rahman Al-Sufi
- (903-986 AD) He made many observations on the obliquity of the ecliptic and the motion of the sun.
He became famous for his observations and descriptions of the stars,
their positions, magnitudes and colour, tabulating his results constellation by constellation.
He also wrote extensively on the astrolabe, finding numerous additional uses for it.
Along with with other learned Muslims, he also highlighted the shortcomings of Greek astronomy.
- Mohammad Abu'l-Wafa Al-Buzjani
- (940-998) The 10th century's greatest mathematician, he was also an astronomer. He moved to 'Adud ad-Dawlah's
court in Baghdad in 959 where he was not the only distinguished scientist at the Caliph's court in Baghdad.
In 988 the Caliph opened a new observatory with a number of famous scientists present such as al-Quhi and Abu'l-Wafa.
The instruments in the observatory included a quadrant over 6 metres long and a stone sextant of 18 metres. Abu'l-Wafa
is said to have been the first to build a wall quadrant to observe the stars. Amongst other things he wrote
commentaries on Euclid, Diophantos and al-Khwarizmi which have all been lost. However evidence remains of his
astronomical tables, a complete book of practical arithmetic and a book of applied geometry.
- Abu Rayhan Al-Biruni
- (973-1050 AD)Scientist, physicist, astronomer, sociologist, linguist, historian and mathematician whose
true worth may never be fully appreciated. He claimed that the earth rotated around its own axis.
He calculated the earth circumference, and fixed scientifically the direction of Mecca from any point of the globe.
He wrote in total 150 works, including 35 treatises on pure astronomy, of which only six have survived.
He is considered the father of unified field theory by Nobel Laureate, the late Professor Abdus Salam.
Abu Rayhan Al-Biruni, Biography
- Al-Zarqali
- (1029-1087 AD) An eminent Andalusian astronomer of the 11th century who was probably the foremost astronomer
of his time. He made his name in different domains of theoretical and practical astronomy and left works that
greatly influenced his scietists of the Islamic, Andalusian and North-African and Latin astronomical traditions,
until Copernicus arrived in the 16th century.
- Jabir ibn Aflah
- (Died circa 1145 AD) He was the first to design a portable celestial sphere to measure and explain the
movements of celestial objects. He is specially noted for his work on spherical trigonometry.
Jabir ibn Aflah, Biography
- Al-Bitruji
- (Died circa 1204 AD) Nur Al-Din Ibn Ishaq Al-Bitruji was born in Morocco, lived in Ishbiliah (Seville)
He worked hard, unsuccessfully, at modifying Ptolemy's system of planetary motions. Al-Bitruji's book
Kitab-al-Hay'ah was popular in thirteenth century Europe.
- Ulugh Beg
-
(1393-1449)He was the grandson of Tamerlane. He was primarily a scientist, specifically a mathematician and an astronomer.
In 1417 he began building a centre for higher education and an observatory at Samarkand. The Observatory was over 50
metres in diameter and 35 metres high. The director of the Observatory was Ali-Kudschi, a Muslim astronomer. Al-Kashi
and other mathematicians and astronomers appointed to the madrasah also worked here. The Observatory had a quadrant so
large that part of the ground had to be removed to allow it to fit in the Observatory. There was also a sextant, a
triquetram and an armillary sphere. Work done was on methods for giving accurate approximate solutions of cubic
equations; work with the binomial theorem. He produced accurate tables of sines and tangents correct to eight decimal
places; formulae of spherical trigonometry; and of particular importance, his Catalogue of the stars, the first
comprehensive stellar catalogue since that of Ptolemy. This star catalogue, the Zij-i Sultani, set the standard for such
works up to the seventeenth century. Published in 1437, it gives the positions of 992 stars. The catalogue was the
results of a combined effort by a number of people working at the Observatory including Ulugh Beg, al-Kashi, and Qadi
Zada. he observations made by these astronomrs discovered a number of errors in the computations of Ptolemy which had
been accepted without question up to that time. Data from their observations allowed the calculation of the length of
the year as 365 days 5 hours 49 minutes 15 seconds, quite an accurate value. Data was produced regarding the Sun, the
Moon and the planets. This data was, like so much of his work, extremly accurate, the difference between Ulugh Beg's
data and that of modern times relationg to falls within the limits of two to five seconds.
- Hindu Astronomy
-
The earliest references to Ancient India's contributions in the field of astronomy are found in the Rig Veda, dated 2000
BC. During next 2500 years, by 500 AD, ancient Indian astronomy has emerged as an important area of study. As
with other ancient societies astronomy was used to explain matters astrological. Apart from this the science
of astronomy continued to develop independently, and culminated into original findings, like:
- The occurrences of eclipses
- The Earth's circumference
- The theory of gravitation
- Determination that the sun was a star
- The determination of number of planets in our solar system
The second millennium text Vedanga Jyotisha went beyond the earlier calendrical astronomy to develop a theory for the
mean motions of the sun and the moon. This marked the beginnings of the application of mathematics to the motions of the
heavenly bodies. The recursive Vedic world-view requires that the universe itself go through cycles of creation and destruction.
This view became a part of the astronomical framework and ultimately very long cycles of billions of years were assumed.
- Notable Hindu Astronomers
- Yajnavalkya
- (Circa 1800 BC) Was a legendary sage of Vedic India, credited with the authorship of the Shatapatha Brahmana.
According to the Indian tradition, he was the son of sage and was the pupil of sage Once.
Hismain contribution to astronomy was a 95-year cycle to harmonize the motions of the sun and the moon
and he also knew that the sun's circuit was asymmetric.
- Lagadha
- (Somewhere between 500-100 BC)
Wrote the "Vedanga Jyotisha". The text is foundational to the Jyotisha discipline of Vedanga. It describes rules for
tracking the motions of the sun and the moon. Lagadha describes astronomy as the crowning subject in the ancillary
Vedic studies.
- Aryabhata the Elder
- (476-550 AD)
Born in Ashmaka, he was the first great Indian astronomer. In his book, the Aryabhatya, he postulated a
mathematical system that said the earth spun on its axis and stated the motions of the planets with respect to the sun
- in other words heliocentric. Aryabhata calculated the Lunar month to be 27.3964693572 days, and is perhaps the
oldest astronomical constant calculated to such accuracy.
Aryabhata the Elder, Biography
- Brahmagupta
- (598-668 AD)
Son of Jisnugupta, wrote important works on mathematics and astronomy. He became the head of the
astronomical observatory at Ujjain writing several texts on astronomy, in particular the Brahmasphutasiddhanta (The
Opening of the Universe). Topics covered - mean longitudes of the planets; true longitudes of the planets; the three
problems of diurnal rotation; lunar eclipses; solar eclipses; risings and settings; the moon's crescent; the moon's
shadow; conjunctions of the planets with each other; and conjunctions of the planets with the fixed stars. His
understanding of numbers was far in advance of others mathematicians of the period. He defined zero as the result of
subtracting a number from itself and got most of the other mathematical concepts of zero correct.
Brahmagupta, Biography
- Bhaskaracharya
- (1114-1185 AD)
His father was a Brahmin named Mahesvara. Bhaskaracharya became head of the astronomical
observatory at Ujjain, the leading mathematical centre in India at that time. In many ways Bhaskaracharya represents the
peak of mathematical knowledge in the 12th century. He reached an understanding of the number systems and solving
equations which was not to be achieved in Europe for several centuries. Six works by Bhaskaracharya are known but for
astronomy the most imortant were Siddhantasiromani - on mathematical astronomy and the sphere, and the Karanakutuhala
(Calculation of Astronomical Wonders). His astronomy texts were similar in layout to many other Indian astronomy texts
of this and earlier periods, covering the topics as described for Brahmagupta, plus syzygies, latitudes of the planets,
and the patas of the sun and moon. [At this date your author has been unable to find a contextual definition of the
word "pata". If anyone out there can enlighten... please eMail me]
Bhaskaracharya, Biography
- Madhava
- (1350-1425 AD)
Madhava of Sangamagramma was born near Cochin on the coast in the Kerala state in south-west India. It is only due to research into Keralese
mathematics that have put his achievement into context: "He took the decisive step onwards from the finite procedures of
ancient mathematics to treat their limit-passage to infinity". All his mathematical writings have been lost, though some
of his texts on astronomy have survived. His brilliant work in mathematics has been largely discovered through the
reports of other Keralese mathematicians such as Nilakantha who lived about 100 years later.
- Nilakantha Somayaji
- (1444-1544 AD)
He was born near Tirur in south India. Nilakantha studied astronomy and Vedanta. He was taught by Damodra. A number of
texts on mathematical astronomy written by Nilakantha have survived. In all he wrote about ten treatises on astronomy.
The Tantrasamgraha is his major astronomy treatise written in 1501. Various aspects of Indian astronomy are covered
which are all based on the epicyclic and eccentric models of planetary motion. Subjcts include the motions and
longitudes of the planets, problems related with the sun's position on the celestial sphere, the lunar and solar
eclipse, the deviation of the longitudes of the sun and the moon. Further it discusses the rising and setting of the
moon and planets. Finally it examines the size of the part of the moon which is illuminated by the sun and gives a
graphical representation of it.
Nilakantha Somayaji, Biography
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