D'Alembert (crater)

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Crater characteristics
Coordinates	50.8° N, 163.9° E
Diameter	248 km
Depth	Unknown
Colongitude	201° at sunrise
Eponym	Jean d'Alembert

D'Alembert is a large lunar impact crater that is located in the northern hemisphere on the far side of the Moon. It is located to the northeast of the Campbell walled plain, a somewhat smaller formation. Laying astride the southwest rim of D'Alembert is the Slipher crater. To the north is Yamamoto crater, and to the south-southwest lies Langevin crater. This walled plain has the same diameter as Clavius crater on the near side, making it one of the largest such formations on the Moon.

As with many lunar walled plains of comparable dimensions, the outer rim of this formation has been worn and battered by subsequent impacts. Besides Slipher crater, the most notable of these craters is 'D'Alembert Z' intruding into the northern rim. There is also a small crater on the northwest inner wall that has a wide cleft in its eastern side, and a smaller crater along the southeastern inner wall. As eroded as the rim may be, its form can still be readily discerned as a roughly circular ridge line in the lunar terrain.

The interior floor of D'Alembert is a relatively level surface, at least in comparison with the rough terrain that surrounds the crater rim. It is marked with a number of small crater impacts, the largest being 'D'Alembert G' and 'D'Alembert E' toward the eastern rim. In the southwest, the floor is more irregular due to the outer rampart and layers of ejecta from Slipher crater. A pair of shallow clefts in the floor surface radiate away from this crater, beginning near the mid-point of D'Alembert and reaching half-way toward the inner wall.

[edit] 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 d'Alembert crater.

d'Alembert	Latitude	Longitude	Diameter
E	52.8° N	168.2° E	22 km
G	50.9° N	167.5° E	18 km
J	47.5° N	170.4° E	20 km
Z	55.4° N	165.6° E	44 km

[edit] References

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