Hipparchus is the degraded remnant of a lunar

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...

. It is located to the southeast of Sinus Medii

Sinus Medii

Sinus Medii is a small lunar mare that is located at the intersection of the Moon's equator and prime meridian. As seen from the Earth, this feature is located in the central part of the Moon's near side, and it is the point closest to the Earth...

, near the center of the visible 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...

. To the south is the prominent crater Albategnius

Albategnius (crater)

Albategnius is an ancient lunar impact crater located in the central highlands. It is named after the Muslim astronomer and scientist Al-Battani. The level interior forms a "walled plain", surrounded by the high, terraced rim. The outer wall is somewhat hexagon-shaped, and has been heavily eroded...

, and to the southwest lies Ptolemaeus

Ptolemaeus (lunar crater)

Ptolemaeus is an ancient lunar impact crater close to the center of the near side. To the south-southeast Ptolemaeus is joined to the rim of the crater Alphonsus by a section of rugged, irregular terrain, and these form a prominent chain with Arzachel to the south...

, a feature of comparable dimensions to Hipparchus. Horrocks

Horrocks (crater)

Horrocks is a lunar impact crater located entirely within the eroded northeast rim of the much larger walled plain Hipparchus. To the south of Horrocks are the craters Halley and Hind and Rhaeticus to the north. Gyldén and Saunder lie to the west and east, respectively...

 lies entirely within the northeast rim of the crater. Halley

Halley (lunar crater)

Halley is a lunar impact crater that is intruding into the southern wall of the walled plain Hipparchus. To the southwest of Halley is the large crater Albategnius, and due east lies the slightly smaller Hind....

 is attached to the south rim, and Hind

Hind (crater)

Hind is a lunar impact crater that lies to the southeast of the walled plain Hipparchus, and due east of the crater Halley. The rim of Hind is relatively free of wear and distortion, except for a break at the north rim. The floor of Hind is relatively uneven, however, compared to the interior of...

 lies to the southeast. To the north-northeast is the bowl-shaped Pickering

Pickering (lunar crater)

Pickering is a small lunar impact crater located to the northeast of the worn walled plain Hipparchus in the central region of the Moon. It lies to the northeast of the crater Horrocks, which lies within Hipparchus. To the southeast is the lava-flooded Saunder....

, and the flooded Saunder

Saunder (crater)

Saunder is a lunar crater located in the central highland region of the Moon, to the east-northeast of the walled plain Hipparchus. The outer wall is irregular and broken in several locations, forming the overall shape of a pentagon. The interior of Saunder has been flooded with lava, forming a...

 is located off the northeast rim.

Hipparchus is where the Moon rocket lands in The Adventures of Tintin

Tintin (character)

Tintin is a fictional character in The Adventures of Tintin, the series of classic Belgian comic books written and illustrated by Hergé. Tintin is the protagonist of the series, a reporter and adventurer who travels around the world with his dog Snowy....

's "Explorers on the Moon

Explorers on the Moon

Explorers on the Moon, published in 1954, is the seventeenth of The Adventures of Tintin, a series of classic comic-strip albums, written and illustrated by Belgian writer and illustrator Hergé, featuring young reporter Tintin as a hero. Its original French title is On a marché sur la Lune...

."

Description

This feature is an ancient crater that has been subject to considerable modification due to subsequent impacts. The western rim of Hipparchus has been all but worn away from impact erosion, and only low hills and rises in the surface remain to outline the feature. The wall to the east is somewhat more intact, but it too is heavily worn. A pair of deep clefts lie in the western wall. These parallel a sets of scars running through the south-central highlands.

The crater floor has been partially resurfaced by basalt

Basalt

Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

ic 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...

 flow. The southwest part of the floor, however, is slightly raised and much more rugged than the remainder. A few small rises and the raised partial rim of a flooded crater are all that remain of a central massif.

Gaps in the northwest rim of Hipparchus form valleys that connect with the mare to the northwest. A rille

Rille

Rille is typically used to describe any of the long, narrow depressions in the lunar surface that resemble channels. Typically a rille can be up to several kilometers wide and hundreds of kilometers in length...

 named Rima Réaumur runs from this site to the outer wall of Réaumur

Réaumur (crater)

Réaumur is the remains of a lunar crater located on the southern edge of Sinus Medii. It lies to the northwest of the large walled plain Hipparchus, and east of Flammarion. To the south is Gyldén, and farther to the south-southwest is Ptolemaeus....

.

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 Hipparchus.

Hipparchus	Latitude	Longitude	Diameter
B	6.9° S	1.7° E	5 km
C	7.3° S	8.2° E	17 km
D	4.5° S	2.1° E	5 km
E	4.2° S	2.3° E	5 km
F	4.2° S	2.5° E	9 km
G	5.0° S	7.4° E	15 km
H	5.4° S	2.3° E	5 km
J	7.6° S	3.2° E	14 km
K	6.9° S	2.2° E	12 km
L	6.8° S	9.0° E	13 km
N	4.8° S	5.0° E	6 km
P	4.7° S	2.8° E	5 km
Q	8.5° S	2.9° E	8 km
T	7.1° S	3.6° E	8 km
U	6.7° S	3.6° E	8 km
W	5.0° S	7.8° E	5 km
X	5.7° S	4.9° E	17 km
Z	8.5° S	9.1° E	6 km