Meton of Athens (; ''gen''.: Μέτωνος) was a

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...

, geometer, and

engineer Engineers, as practitioners of engineering, are professionals who Invention, invent, design, build, maintain and test machines, complex systems, structures, gadgets and materials. They aim to fulfill functional objectives and requirements while ...

who lived in

Athens Athens ( ) is the Capital city, capital and List of cities and towns in Greece, largest city of Greece. A significant coastal urban area in the Mediterranean, Athens is also the capital of the Attica (region), Attica region and is the southe ...

in the 5th century BC. He is best known for calculations involving the eponymous 19-year

Metonic cycle The Metonic cycle or enneadecaeteris (from , from ἐννεακαίδεκα, "nineteen") is a period of almost exactly 19 years after which the lunar phases recur at the same time of the year. The recurrence is not perfect, and by precise obser ...

, which he introduced in 432 BC into the

lunisolar A lunisolar calendar is a calendar in many cultures, that combines monthly lunar cycles with the solar year. As with all calendars which divide the year into months, there is an additional requirement that the year have a whole number of months ...

Attic calendar The Attic calendar or Athenian calendar is the lunisolar calendar beginning in midsummer with the lunar month of Hekatombaion, in use in ancient Attica, the ancestral territory of the Athenian polis. It is sometimes called the Greek calendar bec ...

. Euphronios says that Colonus was Meton's

deme In Ancient Greece, a deme or (, plural: ''demoi'', δήμοι) was a suburb or a subdivision of Classical Athens, Athens and other city-states. Demes as simple subdivisions of land in the countryside existed in the 6th century BC and earlier, bu ...

Work

The

Metonic calendar The Metonic cycle or enneadecaeteris (from , from ἐννεακαίδεκα, "nineteen") is a period of almost exactly 19 years after which the lunar phases recur at the same time of the year. The recurrence is not perfect, and by precise obser ...

incorporates knowledge that 19

solar year A tropical year or solar year (or tropical period) is the time that the Sun takes to return to the same position in the sky – as viewed from the Earth or another celestial body of the Solar System – thus completing a full cycle of astronom ...

s and 235

lunar month In lunar calendars, a lunar month is the time between two successive syzygies of the same type: new moons or full moons. The precise definition varies, especially for the beginning of the month. Variations In Shona, Middle Eastern, and Euro ...

s are very nearly of the same duration. Consequently, a given day of a lunar month will often occur on the same day of the solar year as it did 19 years previously. Meton's observations were made in collaboration with

Euctemon Euctemon (, ''gen.'' Εὐκτήμωνος; fl. 432 BC) was an Athenian astronomer. He was a contemporary of Meton and worked closely with this astronomer. Little is known of his work apart from his partnership with Meton and what is mentioned b ...

, about whom nothing else is known. The Greek astronomer Callippus expanded on the work of Meton, proposing what is now called the Callippic cycle. A Callippic cycle runs for 76 years, or four Metonic cycles. Callippus refined the lunisolar calendar, deducting one day from the fourth Metonic cycle in each Callippic cycle (i.e., after 940 synodic lunar periods had elapsed), so as to better keep the lunisolar calendar synchronized with the seasons of the solar year. The world's oldest known astronomical calculator, the

Antikythera Mechanism The Antikythera mechanism ( , ) is an Ancient Greece, Ancient Greek hand-powered orrery (model of the Solar System). It is the oldest known example of an Analog computer, analogue computer. It could be used to predict astronomy, astronomical ...

(2nd century BC), performs calculations based on both the Metonic and Callipic calendar cycles, with separate dials for each. The foundations of Meton's observatory in Athens are still visible just behind the podium of the Pnyx, the ancient parliament. Meton found the dates of equinoxes and solstices by observing sunrise from his observatory. From that point of observation, during the

summer solstice The summer solstice or estival solstice occurs when one of Earth's poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere ( Northern and Southern). The summer solstice is the day with the longest peri ...

, sunrise was in line with the local hill of Mount Lycabetus, while six months later, during the

winter solstice The winter solstice, or hibernal solstice, occurs when either of Earth's geographical pole, poles reaches its maximum axial tilt, tilt away from the Sun. This happens twice yearly, once in each hemisphere (Northern Hemisphere, Northern and So ...

, sunrise occurs over the high brow of Mount Hymettos in the southeast. So from Meton's observatory the Sun appears to move along a 60° arc between these two points on the horizon every six months. The bisector of the observatory's solstitial arc lies in line with the Acropolis. These topological features are important because the summer solstice was the point in time from which the Athenians measured the start of their calendar years. The first month of the new year, Hekatombaion, began with the first new moon after the summer solstice.Hannah, R. 'Greek and Roman Calendars'. London: Duckworth, pages 52-55. Meton appears briefly as a character in

Aristophanes Aristophanes (; ; ) was an Ancient Greece, Ancient Greek Ancient Greek comedy, comic playwright from Classical Athens, Athens. He wrote in total forty plays, of which eleven survive virtually complete today. The majority of his surviving play ...

' play '' The Birds'' (414 BC). He comes on stage carrying

surveying Surveying or land surveying is the technique, profession, art, and science of determining the land, terrestrial Plane (mathematics), two-dimensional or Three-dimensional space#In Euclidean geometry, three-dimensional positions of Point (geom ...

instruments and is described as a geometer. What little is known about Meton is related by ancient historians. According to

Ptolemy Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...

, a

stela A stele ( ) or stela ( )The plural in English is sometimes stelai ( ) based on direct transliteration of the Greek, sometimes stelae or stelæ ( ) based on the inflection of Greek nouns in Latin, and sometimes anglicized to steles ( ) or stela ...

or table erected in Athens contained a record of Meton's observations, and a description of the Metonic cycle. None of Meton's works survive.

Notes

References

* * Pannekoek, A. "Planetary Theories – the Planetary Theory of Kidinnu." ''Popular Astronomy'' 55, 10/1947, p 422

External links

*
Greek Astronomy
{{DEFAULTSORT:Meton of Athens 5th-century BC Athenians Ancient Greek astronomers Ancient Greek engineers 5th-century BC Greek mathematicians 5th-century BC astronomers Summer solstice