Eratosthenes
Location: ·
This crater lends its name to a whole lunar era — the Eratosthenian period, ~3.2 to 1.1 billion years ago.
Eratosthenes is the type crater of the Eratosthenian period, defined as the span in which craters formed with fresh morphology but whose rays have since faded. It sits directly against Copernicus in the same landscape and the pair fix the boundary between the two youngest lunar periods: both are sharp-rimmed and terraced, but only Copernicus still has rays.
That the difference is one of surface maturity and not of form is the whole content of the boundary, and it is why the Copernican-Eratosthenian division is the least securely dated in the lunar timescale.
Sunrise
Sunset
Sunrise and sunset on Eratosthenes
| Event | Time | Lit |
|---|---|---|
| Computing… | ||
- Sunrise / Sunset: at the feature's centre (IAU Gazetteer of Planetary Nomenclature).
- Lit: the illuminated fraction of the Moon's disc at that moment.
Named after
Eratosthenes of Cyrene, Greek astronomer and geographer (c. 276–196 BC).
Further info
Official record from the IAU Gazetteer of Planetary Nomenclature: Eratosthenes
Wikipedia: Eratosthenes (crater)