Neper (crater)
Encyclopedia
Neper is an old lunar
impact crater
located near the eastern limb of the Moon
. Due to its location the crater must be viewed during a suitable libration
, and is very foreshortened. The crater lies on the south edge of Mare Marginis
, to the east of the crater Jansky
. To the northwest across the Mare Marginis
is the crater Goddard
.
The crater inner walls have worn terraces, with low rim edges at the northern and southern extremes. The crater floor is dark and flat, with a central peak and several crater impacts near the west rim. The most notable of these is a small crater near the north-northwestern edge.
It is named after the Scottish
mathematician, physicist, astronomer and astrologer John Napier
.
The following craters have been renamed by the IAU
.
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...
located near the eastern limb of the Moon
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...
. Due to its location the crater must be viewed during a suitable libration
Libration
In astronomy, libration is an oscillating motion of orbiting bodies relative to each other, notably including the motion of the Moon relative to Earth, or of Trojan asteroids relative to planets.-Lunar libration:...
, and is very foreshortened. The crater lies on the south edge of Mare Marginis
Mare Marginis
Mare Marginis is a lunar mare that lies on the very edge of the lunar nearside. The selenographic coordinates of this feature are 13.3° N, 86.1° E, and the diameter is 420 km. The name is Latin for "Sea of the Edge"....
, to the east of the crater Jansky
Jansky (crater)
Jansky is a lunar impact crater that lies along the eastern limb of the Moon. It lies due east of the larger walled plain Neper, along the southern edge of the Mare Marginis. Due to its location, this crater is viewed from the side from Earth, limiting the amount of detail that can be observed...
. To the northwest across the Mare Marginis
Mare Marginis
Mare Marginis is a lunar mare that lies on the very edge of the lunar nearside. The selenographic coordinates of this feature are 13.3° N, 86.1° E, and the diameter is 420 km. The name is Latin for "Sea of the Edge"....
is the crater Goddard
Goddard (crater)
Goddard is a lunar crater that is located along the eastern limb of the Moon, and so is visible from the edge from Earth. It is best viewed during favorable librations when the orientation of the Moon brings it further into sight. The crater is located in the Mare Marginis, to the northeast of the...
.
The crater inner walls have worn terraces, with low rim edges at the northern and southern extremes. The crater floor is dark and flat, with a central peak and several crater impacts near the west rim. The most notable of these is a small crater near the north-northwestern edge.
It is named after the Scottish
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
mathematician, physicist, astronomer and astrologer John Napier
John Napier
John Napier of Merchiston – also signed as Neper, Nepair – named Marvellous Merchiston, was a Scottish mathematician, physicist, astronomer & astrologer, and also the 8th Laird of Merchistoun. He was the son of Sir Archibald Napier of Merchiston. John Napier is most renowned as the discoverer...
.
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 Neper.| Neper | Latitude | Longitude | Diameter |
|---|---|---|---|
| D | 9.2° N | 80.8° E | 40 km |
| H | 10.4° N | 78.2° E | 9 km |
| Q | 8.0° N | 83.1° E | 12 km |
The following craters have been renamed by the IAU
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
.
- Neper G - See Virchow (crater)Virchow (crater)Virchow is a small lunar impact crater that is located on the northwestern interior floor of the prominent crater Neper. The latter formation lies near the eastern limb of the Moon, along the southern edge of the Mare Marginis. Observation of this area is hindered due to foreshortening, as well as...
. - Neper K - See Tacchini (crater)Tacchini (crater)Tacchini is a lunar crater on the northwestern edge of the Mare Smythii, near the eastern limb of the Moon. It lies just to the south of the prominent crater Neper, and was designated Neper K before being given its current name by the IAU...
.