Euclides is a small lunar

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...

located near the eastern edge of

Oceanus Procellarum Oceanus Procellarum ( la, Ōceanus procellārum, lit=Ocean of Storms) is a vast lunar mare on the western edge of the near side of the Moon. It is the only one of the lunar maria to be called an "Oceanus" (ocean), due to its size: Oceanus Proc ...

, about 30 kilometers to the west of the Montes Riphaeus mountains. The

mare A mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three, and a filly is a female horse three and younger. In Thoroughbred horse racing, a mare is defined as a female horse more than f ...

in the vicinity is devoid of significant craters, but to the west is an area of low rises. The crater is named after the

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Euclid Euclid (; grc-gre, Εὐκλείδης; BC) was an ancient Greek mathematician active as a geometer and logician. Considered the "father of geometry", he is chiefly known for the ''Elements'' treatise, which established the foundations of ...

. Euclides is a bowl-shaped formation with a circular rim. It is surrounded by streaks of ejecta that have a higher

albedo Albedo (; ) is the measure of the diffuse reflection of solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that refl ...

than the nearby maria. This nebulous skirt of light-hued material makes this feature very prominent under a high Sun, and it is one of the brightest sites on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width ...

Euclides D

Euclides D is a small lunar impact crater in the Mare Cognitum. It has a diameter of 6 kilometers and a depth of 1.3 kilometers. It lies to the southeast of Euclides, beyond the Montes Riphaeus mountains. In 1976, Euclides D was renamed ''Eppinger'' by the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

to honor Hans Eppinger, a professor of pathological

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...

Graz Graz (; sl, Gradec) is the capital city of the Austrian state of Styria and second-largest city in Austria after Vienna. As of 1 January 2021, it had a population of 331,562 (294,236 of whom had principal-residence status). In 2018, the popu ...

. However, in 2002, after Eppinger's association with Nazi prison camps had been brought to the attention of the IAU's ''Working Group for Planetary System Nomenclature'', the name was reverted to Euclides D.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Euclides. The following craters have been renamed by the

. * Euclides B — ''See'' Norman.

Gallery

Euclides D crater 4125 h3.jpg, Lunar Orbiter 4 image of Euclides D Euclides_crater_AS16-P-5454.jpg, Oblique Panoramic Camera image of Euclides from Apollo 16 Euclides crater AS16-M-2522.jpg, Oblique regional view also from Apollo 16

References

* * * * * * * * * * * * Impact craters on the Moon {{Craters on the Moon: C-F

Euclides D

Satellite craters

Gallery

See also

References