Hirayama (crater)


Hirayama is a large lunar impact crater that is located on the far side of the Moon, just beyond the eastern limb. This region of the surface is sometimes brought into view from Earth during periods of favourable libration. However it is best viewed from orbit. This crater is located along the southeastern edge of the Mare Smythii, to the northeast of the crater Brunner. To the northeast of Hirayama is Wyld.
This is a worn and eroded crater with multiple impacts overlapping the outer rim and the interior floor. Hirayama K has broken across the rim to the southeast and Hirayama C crosses the northeastern rim. Along the southwestern outer edge is Hirayama Q. The small Hirayama T is located along the western inner wall, and attached to its eastern edge is Hirayama S. The crater Hirayama Y is adjacent to the northern inner walls of Hirayama and covers a significant part of the northern interior floor. Several smaller craters lie within the floor, including Hirayama N in the south. The floor otherwise forms a relatively level surface within the inner wall.

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 Hirayama.
HirayamaLatitudeLongitudeDiameter
C4.2° S95.4° E23 km
F5.8° S97.2° E35 km
G6.4° S96.8° E18 km
K8.3° S94.9° E39 km
L9.4° S94.4° E24 km
M9.2° S93.5° E29 km
N7.2° S93.6° E17 km
Q8.0° S91.3° E40 km
S6.5° S92.3° E29 km
T6.4° S91.5° E18 km
Y4.5° S93.2° E50 km

The names Tolstoy, Montesquieu, Longfellow, and Balzac were proposed for satellite craters Y, S, Q, and K, respectively, but were not approved by the IAU.