What is the Metonic cycle?

The Metonic cycle is a 19-year lunar solar calendar.

How many months are in the Metonic calendar?

The Metonic calendar consists of 235 lunar months.

The intercalary 13th month is added to maintain seasonal alignment in the Metonic calendar.

Months are displayed in groups of five on the five spiral dial.

The Metonic calendar is of Corinthian origin, associated with the ancient region of Epirus.

The mechanism is a sophisticated lunar solar calendar following the 19-year Metonic cycle, utilizing a five-turn spiral layout for 235 lunar months and incorporating 12 lunar months synchronized with local seasons through an intercalary 13th month system.
The intricate design of the mechanism, with month names inscribed in ancient Greek, a radial pattern of five spirals, and detailed engravings possibly crafted with a burin-style tool, suggests a high level of craftsmanship and precision in its construction, likely originating from the tradition of device-making in Rhodes.

What is the Metonic cycle?
The Metonic cycle is a 19-year lunar solar calendar.
How many months are in the Metonic calendar?
The Metonic calendar consists of 235 lunar months.
What is the purpose of the intercalary 13th month?
The intercalary 13th month is added to maintain seasonal alignment in the Metonic calendar.
How are months displayed on the spiral dial?
Months are displayed in groups of five on the five spiral dial.
What is the origin of the Metonic calendar?
The Metonic calendar is of Corinthian origin, associated with the ancient region of Epirus.

00:00

The mechanism reveals a lunar solar calendar based on the 19-year Metonic cycle with 235 lunar months laid out around a five-turn spiral.
The calendar includes 12 lunar months in series cycled through with a system of regulation to synchronize with local seasons.
A set of rules specifies when to add an intercalary 13th month to maintain seasonal alignment in the Metonic calendar.
The 235 months are laid out in a radial pattern of five spirals, with seven intercalary years of 13 months in duration spread out across the sequence of 19.
110 months are prescribed to drop a day to be 29 days in duration, conveniently displayed in 22 groups of five on the five spiral dial.
The month names on the mechanism are inscribed in ancient Greek, divided mostly by syllable over two or three lines with characters just over one millimeter tall.
The calendar is of Corinthian origin, associated with the ancient region of Epirus, and intended to be interpreted with subsidiary dials for games and the Callippic cycle.
The mechanism may have been associated with the device-making tradition of Rhodes, with the Games dial possibly indicating the construction location.
The engraving work on the mechanism suggests the use of a burin-style cutting tool made of tempered martensite, capable of producing fine, crisply engraved detail.
Numbers on the mechanism are indicated using the Greek letters-for-numbers system, providing a comprehensive layout of excluded days for the entire 235 month cycle.