Meton of Athens | |
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| Died | Greece |
| Occupations | Mathematician,astronomer,geometer,engineer |
Meton of Athens (Greek:Μέτων ὁ Ἀθηναῖος;gen.: Μέτωνος) was aGreekmathematician,astronomer,geometer, andengineer who lived inAthens in the 5th century BC. He is best known for calculations involving the eponymous 19-yearMetonic cycle, which he introduced in 432 BC into thelunisolarAttic calendar. Euphronios says thatColonus was Meton'sdeme.[1]
TheMetonic calendar incorporates knowledge that 19solar years and 235lunar months 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 withEuctemon, about whom nothing else is known. The Greek astronomerCallippus expanded on the work of Meton, proposing what is now called theCallippic 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, theAntikythera Mechanism (2nd century BC), performs calculations based on both the Metonic and Callipic calendar cycles, with separate dials for each.[2][3]
The foundations of Meton's observatory in Athens are still visible just behind the podium of thePnyx, the ancient parliament. Meton found the dates of equinoxes and solstices by observing sunrise from his observatory. From that point of observation, during thesummer solstice, sunrise was in line with the local hill of Mount Lycabetus, while six months later, during thewinter solstice, 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.[4]
Meton appears briefly as a character inAristophanes' playThe Birds (414 BC). He comes on stage carryingsurveying instruments and is described as ageometer.
What little is known about Meton is related by ancient historians. According toPtolemy, astela or table erected in Athens contained a record of Meton's observations, and a description of the Metonic cycle.[5] None of Meton's works survive.
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