Desargues (crater)
Encyclopedia
Desargues is an ancient lunar
crater
that is located near the northern limb of the Moon
, on the western hemisphere
. It lies nearly due south of the crater Pascal
, and southeast of Brianchon
. The proximity of this crater to the limb means that it appears highly elongated due to foreshortening, and it is difficult to discern details from the Earth
.
This formation has been significantly eroded and degraded with the passage of time, leaving a low, irregular rim that has been reshaped by subsequent impacts. The rim has a notable bulge to the northeast, and a lesser bulge along the southern rim. The later remains as an imprint of a ghost crater
in the surface that overlies the southern rim, and leaves a remnant of its northern rim in the crater floor.
The bulge to the northeast has left a remnant of its origin in the crater floor, as a series of low hills extending from the north and southeast. These enclose the northeastern third of the floor, and are suggestive of an overlapping crater formation. This crater is overlain in turn by a pair of craters that lie across the eastern rim.
The floor of the crater is level and has most likely been resurfaced by subsequent lava
flows, or by fallback and ejecta deposits. This wiped away much of the original structure of the interior, leaving ridges and traces where once lay crater rims. Other lesser craters intrude into the rim, with Desargues M forming a bulge into the southern rim and Desargues A overlying the northern rim.
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...
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 is located near the northern 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...
, on the western hemisphere
Sphere
A sphere is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle in two dimensions, a perfect sphere is completely symmetrical around its center, with all points on the surface lying the same distance r from the center point...
. It lies nearly due south of the crater Pascal
Pascal (crater)
Pascal is a lunar crater that lies near the northern limb of the Moon, on the western side of the pole. It is located to the north of the eroded crater Desargues, and just east of Brianchon. Pascal can be located by finding the crater Carpenter and then following the surface to the northwest...
, and southeast of Brianchon
Brianchon (crater)
Brianchon is a lunar crater that is located along the northwestern limb of the Moon. Due to its location, from the Earth the crater is seen from the edge and its visibility is somewhat affected by libration. Thus for a more detailed view, the crater must be viewed from orbit.This crater lies just...
. The proximity of this crater to the limb means that it appears highly elongated due to foreshortening, and it is difficult to discern details from the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
This formation has been significantly eroded and degraded with the passage of time, leaving a low, irregular rim that has been reshaped by subsequent impacts. The rim has a notable bulge to the northeast, and a lesser bulge along the southern rim. The later remains as an imprint of a ghost crater
Palimpsest
A palimpsest is a manuscript page from a scroll or book from which the text has been scraped off and which can be used again. The word "palimpsest" comes through Latin palimpsēstus from Ancient Greek παλίμψηστος originally compounded from πάλιν and ψάω literally meaning “scraped...
in the surface that overlies the southern rim, and leaves a remnant of its northern rim in the crater floor.
The bulge to the northeast has left a remnant of its origin in the crater floor, as a series of low hills extending from the north and southeast. These enclose the northeastern third of the floor, and are suggestive of an overlapping crater formation. This crater is overlain in turn by a pair of craters that lie across the eastern rim.
The floor of the crater is level and has most likely been resurfaced by subsequent lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
flows, or by fallback and ejecta deposits. This wiped away much of the original structure of the interior, leaving ridges and traces where once lay crater rims. Other lesser craters intrude into the rim, with Desargues M forming a bulge into the southern rim and Desargues A overlying the northern rim.
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 Desargues.| Desargues | Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 71.4° N | 75.3° W | 30 km |
| B | 70.7° N | 65.0° W | 50 km |
| C | 69.7° N | 78.4° W | 12 km |
| D | 69.3° N | 69.6° W | 11 km |
| E | 70.2° N | 67.4° W | 31 km |
| K | 68.5° N | 67.2° W | 10 km |
| L | 69.6° N | 82.2° W | 13 km |
| M | 68.4° N | 73.9° W | 30 km |