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Kepler (lunar crater)
Encyclopedia
Kepler is a lunar
impact crater
that lies between the Oceanus Procellarum
to the west and Mare Insularum
in the east. To the southeast is the crater Encke
.
Kepler is most notable for the prominent ray system
that covers the surrounding mare
. The rays extend for well over 300 kilometers, overlapping the rays from other craters. Kepler has a small rampart of ejecta surrounding the exterior of its high rim. The outer wall is not quite circular, and possesses a slightly polygon
al form. The interior walls of Kepler are slumped and slightly terraced, descending to an uneven floor and a minor central rise.
One of the rays from Tycho
, when extended across the Oceanus Procellarum
, intersects this crater. This was a factor in the choice of the crater's name when Giovanni Riccioli was creating his system of lunar nomenclature
, as Kepler used the observations of Tycho Brahe
while devising his three laws of planetary motion. On Riccioli's maps, this crater was named Keplerus, and the surrounding skirt of higher albedo
terrain was named Insulara Ventorum.
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
that lies between the Oceanus Procellarum
Oceanus Procellarum
Oceanus Procellarum is a vast lunar mare on the western edge of the near side of the Earth's Moon. Its name derives from the old superstition that its appearance during the second quarter heralded bad weather...
to the west and Mare Insularum
Mare Insularum
Mare Insularum is a lunar mare located in the Insularum basin just south of Mare Imbrium. The basin material is of the Lower Imbrian epoch, with the mare material of the Upper Imbrian epoch. The mare is bordered by the craters Copernicus on the east, and Kepler on the west...
in the east. To the southeast is the crater Encke
Encke (crater)
Encke is a lunar crater that is located on the western edge of the Mare Insularum, to the south-southeast of the crater Kepler. The small crater Kunowsky lies to the east-southeast on the mare....
.
Kepler is most notable for the prominent ray system
Ray system
A ray system comprises radial streaks of fine ejecta thrown out during the formation of an impact crater, looking a bit like many thin spokes coming from the hub of a wheel. The rays can extend for lengths up to several times the diameter of their originating crater, and are often accompanied by...
that covers the surrounding mare
Lunar mare
The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...
. The rays extend for well over 300 kilometers, overlapping the rays from other craters. Kepler has a small rampart of ejecta surrounding the exterior of its high rim. The outer wall is not quite circular, and possesses a slightly polygon
Polygon
In geometry a polygon is a flat shape consisting of straight lines that are joined to form a closed chain orcircuit.A polygon is traditionally a plane figure that is bounded by a closed path, composed of a finite sequence of straight line segments...
al form. The interior walls of Kepler are slumped and slightly terraced, descending to an uneven floor and a minor central rise.
One of the rays from Tycho
Tycho (crater)
Tycho is a prominent lunar impact crater located in the southern lunar highlands, named after the Danish astronomer Tycho Brahe . To the south is the crater Street; to the east is Pictet, and to the north-northeast is Sasserides. The surface around Tycho is replete with craters of various sizes,...
, when extended across the Oceanus Procellarum
Oceanus Procellarum
Oceanus Procellarum is a vast lunar mare on the western edge of the near side of the Earth's Moon. Its name derives from the old superstition that its appearance during the second quarter heralded bad weather...
, intersects this crater. This was a factor in the choice of the crater's name when Giovanni Riccioli was creating his system of lunar nomenclature
Planetary nomenclature
Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the surface of a planet or natural satellite so that the features can be easily located, described, and discussed. The task of assigning official names to features is taken up by the International...
, as Kepler used the observations of Tycho Brahe
Tycho Brahe
Tycho Brahe , born Tyge Ottesen Brahe, was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...
while devising his three laws of planetary motion. On Riccioli's maps, this crater was named Keplerus, and the surrounding skirt of higher albedo
Albedo
Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...
terrain was named Insulara Ventorum.
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Kepler.| Kepler | Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 7.2° N | 36.1° W | 11 km |
| B | 7.8° N | 35.3° W | 7 km |
| C | 10.0° N | 41.8° W | 11 km |
| D | 7.4° N | 41.9° W | 10 km |
| E | 7.4° N | 43.9° W | 6 km |
| F | 8.3° N | 39.0° W | 7 km |
| P | 12.2° N | 34.0° W | 4 km |
| T | 9.0° N | 34.6° W | 3 km |