Eratosthenes-centered area in selenochromatic Image (Si) with some landmarks (yellow/normal, red/pyroclastic).Eratosthenes (lower left of center) and surroundings from Apollo 17. NASA image.Eratosthenes crater. Photo taken from Earth. Author: Georgi Georgiev, Stara Zagora, Bulgaria.
The crater has a well-defined circular rim, terraced inner wall, central mountain peaks, an irregular floor, and an outer rampart of ejecta. It lacks a ray system of its own, but is overlain by rays from the prominent crater Copernicus to the south-west.
At low Sun-angles, this crater is prominent due to the shadow cast by the rim. When the Sun is directly overhead, however, Eratosthenes visually blends into the surroundings, and it becomes more difficult for an observer to locate it. The rays from Copernicus lie across this area, and their higher albedo serves as a form of camouflage.
In 1851 Shropshire Astronomer Henry Blunt constructed a model of the Moon's surface showing Eratosthenes. The model is based on observations made by Blunt with a reflecting telescope from his home in Shrewsbury and was displayed in the same year at the Great Exhibition, London.
From 1910 to the 1920s, William H. Pickering noted dark patches in the crater that varied in a regular manner over each lunar day. He first put forward the speculative idea that these patches appeared to migrate across the surface, suggestive of vegetation. Pickering believed that the Moon had a thicker atmosphere and reported seeing climatic variations such as frost and snow, leading him to refer to the crater as the "Gardens of Eratosthenes".[3] Later his views would change, and he would come to believe that the vegetation was instead "swarms of animal life",[4][5] which he often referred to as swarms of insects, or "lunar insects". The scientific community did not share his enthusiasm for these ideas,[6] but they received a degree of attention in the popular press of the time primarily due to Pickering's reputation.
Detail map of Mare Imbrium's features. Eratosthenes is marked "L".
^Sheehan, William; Dobbins, Thomas A. (2001). Epic Moon: A History of Lunar Exploration in the Age of the Telescope. Vol. 410. Willmann-Bell. pp. 250, 251. ISBN0943396700.
McDowell, Jonathan (July 15, 2007). "Lunar Nomenclature". Jonathan's Space Report. Retrieved 2007-10-24.
Menzel, D. H.; Minnaert, M.; Levin, B.; Dollfus, A.; Bell, B. (1971). "Report on Lunar Nomenclature by the Working Group of Commission 17 of the IAU". Space Science Reviews. 12 (2): 136–186. Bibcode:1971SSRv...12..136M. doi:10.1007/BF00171763. S2CID122125855.
Wood, Chuck (June 26, 2004). "Albedo & Rays". Lunar Photo of the Day. Archived from the original on 2018-05-30. Retrieved 2017-09-21.
Wood, Chuck (September 28, 2004). "Unknown Luna 19". Lunar Photo of the Day. Archived from the original on 2008-11-20. Retrieved 2017-10-06. - featuring three released photos from Luna 19 from 1971 - it includes Eratosthenes in the third one
Wood, Chuck (December 10, 2004). "Overlooked Secondaries". Lunar Photo of the Day. Archived from the original on 2018-05-30. Retrieved 2017-09-21.
Media related to Eratosthenes (crater) at Wikimedia Commons
