Statio Tranquillitatis 0.7°N, 23.5°E

On 20 July 1969, the landing module Eagle of the first manned Moon mission, Apollo 11, landed east of the crater Sabine. The landing site is a very flat, level region and was officially named Statio Tranquillitatis. The location was consciously chosen by the planning team, to minimize the dangers to the first landing from an uneven surface and craterlets. The landing approach was from the east, with the Sun behind them. To honour the first manned Moon landing, three small craters were officially named by the IAU after the astronauts: Armstrong (4.6 km), Collins (2.4 km), and Aldrin (3.4 km). Neil Armstrong was the first man to set foot on the Moon, followed by Buzz Aldrin. Collins remained in lunar orbit.

Rimae Hypatia 1.0°S, 23.0°E

A very broad, linear rille on the border between Mare Tranquillitatis and Sinus Asperitatis (the ‘Bay of Asperity’ or ‘Bay of Roughness’), and which splits into a ‘Y’-shape at its eastern end. The crater Moltke B lies right where it splits. The crater pit Moltke AC lies directly on top of the rille. The main segments of Rimae Hypatia are extremely broad and easy to observe even in small telescopes.

Moltke 0.6°S, 24.2°E

South of the Apollo-11 landing site, and north of the main portion of Rimae Hypatia lies the small, but conspicuous circular crater, Moltke (6 km in diameter). It is surrounded by a halo of bright ejecta and served as a navigation marker for Neil Armstrong during the Apollo mission's landing approach.

Arzachel 18.2°S, 1.9°W

Arzachel is younger than Ptolomaeus and Alphonsus. It has a diameter of 96 km. When near the terminator it is an observational highlight for any size of instrument. The inner crater walls are markedly terraced, with a sharp-edged structure, and the long, slightly eccentrically placed central peaks reach 1.5 km above the crater's floor. Many craterlets and the 10-km crater Arzachel A lie on the floor. Arzachel also has a rille system, Rimae Arzachel. The main rille has a length of about 50 km, is significantly wider than the rilles in Alphonsus and follows the curvature of the eastern inner crater wall.

Alpetragius 16.0°S, 4.5°W

Alpetragius is a remarkable looking, circular crater, 39 km in diameter. For its size, it is unusually deep. Its central peak is conical in shape, and is conspicuously large when compared with the crater's diameter. In all probability, the central peak created by the impact was subsequently modified and enlarged through volcanism. Many craters in the vicinity show these broad, conical and unusually large central peaks.

Alphonsus 13.4°S, 2.8°W

Alphonsus is undoubtedly one of the most interesting craters on the nearside of the Moon. On old Moon maps it was described as a ring mountain. The prominent peak of the central mountain is visible, slightly north of the centre of the crater. A distinctive rille system, Rimae Alphonsus, lies on the eastern crater floor.

Eratosthenes 14.5°N, 11.3°W

Eratosthenes is a typical, little-eroded impact crater with a diameter of 58 km. The depth of the crater floor below the rim is 3.6 km. It has a continuous crater rim and strongly terraced inner walls. The central peak reaches a height of 1.5 km above the crater floor. Eratosthenes was formed about 3.2 billion years ago (within the Eratosthenian period on the lunar timescale). Because of its greater age – when comparted with Copernicus (800 million years) – it no longer shows any obvious ray system. The system that formerly existed has, over the course of billions of years, been darkened by lunar erosion and covered by later impacts.

The foothills of the Apennines reach as far as the northeastern wall of the crater. On the southwest lies a nameless range of mountains which stretches south as far as the ghost crater Stadius. The view of Eratosthenes changes greatly throughout a lunation, and at Full Moon it is practically invisible.

Sinus Aestuum 10.9°N, 8.8°W

Sinus Aestuum (‘Bay of Billows’) is a mare-like plain, about 290 km across. It lies between Eratosthenes and the western slopes of the Apennines. The surface shows a few craters and a few ridges similar to mare wrinkle ridges. The low crater count suggests that the lava flows in Sinus Aestuum are relatively young.

Clavius 58.8°S, 14.1°W

Clavius, with its diameter of 245 km and its slightly polygonal shape, is certainly one of the most spectacular complex craters on the nearside of the Moon, and therefore one of the favourite objects for observing with any size of instrument, even in binoculars or a spotting scope. Clavius is suitable as a test object for the determination of a telescope's resolution. The best observation time is shortly before First Quarter (at sunrise) or shortly after Last Quarter (at sunset), but observation is worthwhile at any time that Clavius is illuminated by the Sun. Depending on the angle of incidence of sunlight, different details of the internal structure and its crater walls are revealed. When fully illuminated (at Full Moon) Clavius becomes more or less invisible.

Clavius was formed in the Nectarian period on the lunar timescale. The southern crater wall is broken by the crater Rutherfurd (48 km, 60.9°S, 12.1°W) and the northern wall by Porter (51 km, 56.1°S, 10.1°). Both craters exhibit central mountain massifs. Between Rutherfurd and Porter on the crater floor there are low ridges, like mare wrinkle ridges. Beginning at Rutherfurd, a chain of craters, gradually decreasing in size, stretches in an arc towards the west: Clavius D, then Clavius C, N and J (21 km, 13 km and 12 km, respectively). Clavius D, the largest of these secondary craters has a diameter of about 25 km. On the southern floor of the crater, near the inner crater wall, larger telescopes show dozens of craterlets and crater pits.

Aristarchus 23.7°N, 47.4°W

The crater Aristarchus lies on a rhombus-shaped, high plateau in the northern portion of Oceanus Procellarum and is the boundary between the latter and the lava plain of Sinus Roris. Aristarchus is a very young crater (created about 500 million years ago), with a ray system and a diameter of about 40 km. The crater has a small central peak. The crater's floor lies 3 km below the rim, and is deep enough to have exposed the bright anorthositic rocks of the upper lunar crust through the impact and to transport them to the surface. They also form the ray system of ejecta around the crater. The inner crater walls of Aristarchus have a high albedo and are crossed by dark, radial stripes. The crater and its surroundings are visible even under the ashen-coloured light of Earthshine.

The whole plateau was repeatedly the centre of observation of the so-called Lunar Transient Phenomena, luminous events, perhaps caused by the release of radioactive gases from the Moon's interior. During overflights of the plateau by Apollo 15 and the Lunar Prospector probe, measurements of higher traces of radioactive radon gas were detected. On contrast-enhanced images this area is one of the most colourful areas on the nearside of the Moon.

Vallis Schröteri 26.2°N, 50.8°W

Schröter's Valley is the largest and longest sinuous rille on the Moon, but its origins are not comparable with valleys on Earth. Vallis Schröteri begins about 30 km north of the crater Herodotus at a small crater, only 6 km across, known as the ‘Cobra Head’.

Mare Serenitatis

28.0°N, 17.5°E

Mare Serenitatis, the ‘Sea of Serenity’, is a large, nearly round lava expanse with an area of about 500 × 700 km. Like all the other maria, Mare Serenitatis is also the centre of a gravitational anomaly (a mascon), and it is also a typical multiring basin with at least two basin ramparts. The darker edge regions suggest that this lava is richer in metallic components such as iron and titanium, and that it emerged earlier in the period of lava flows than the lava in the central region. Around the edge, the lava is also thinner than in the centre of the mare.

From soil samples obtained during the Apollo 17 mission (the landing site was on the southeastern edge of the mare), geologists were able to determine that the lava in Mare Serenitatis erupted at different times, almost 800 million years apart (between 3.8 and 3.0 billion years ago). Even on the Earth and for terrestrial geological sequences, this is an enormous time-span. This period was the most active one for lunar volcanism. About 3 billion years ago, the lava flows gradually ceased, but did not stop completely. The last active phase of lava production took place about 1 billion years ago.

The southwestern edge of Mare Serenitatis is bordered by Montes Haemus, a range of mountains that is about 400 km long. The range is the visible remnant of the wall of the Serenitatis Basin.

Palus Somni 14.1°N, 45.0°E

Palus Somni, ‘Marsh of Dreams’, is a diamond-shaped area, lying immediately west of Proclus. It is completely free from ejecta from the Proclus impact, and the ray system separates Palus Somni from Mare Crisium. Palus Somni extends c. 150 km in an east-west direction and appears to be an intermediate geological stage between a highland and a mare floor. The northern portion is rough and fissured, whereas the southern portion is relatively flat, smooth and level. Palus Somni shows conspicuous nuances of colour, which were formerly the subject of numerous geological studies.

Proclus 16.1°N, 46.8°E

Proclus is a very conspicuous, obviously five-sided crater 28 km in diameter. It lies in the western highlands, adjoining Mare Crisium. The crater walls are sharply defined and seem to be little eroded. The floor of the crater is rough and fissured, and the crater walls reach a height of 2.4 km above the crater floor. Proclus is undoubtedly one of the youngest craters. The asymmetric shape of the impact ejecta is visible when the Moon is 5 to 6 days old, and the illumination around Full Moon causes the ray system to be one of the brightest objects on the lunar surface. The longest ray runs northeast, right across Mare Crisium and is c. 600 km long (that is roughly the distance between Boston and Washington).

Archimedes 29.7°N, 4.0°W

Archimedes is one of the most conspicuous craters on the Mare Imbrium with a lava-flooded crater floor, and which was probably created during the early Imbrium period. The inner crater walls are stepped or terraced. The diameter of Archimedes is 82 km and the crater walls reach a height of 2.1 km above the floor. Its considerable diameter suggests that there are central peaks, but these have been completely submerged by the lava. The lava surface inside the crater appears smooth and completely level. Medium-sized instruments show, under favourable lighting conditions, two craterlets; Archimedes T, right over to the west, and Archimedes S, close to the eastern wall of the crater. Both have a diameter of just about 3 km. Large instruments show at least a dozen smaller crater pits. Stripes of bright ejecta, of unknown origin, lie across the lava surface. The ejecta melted by the impact also lies on the upper wall of the crater and gives it a thickened, rounded appearance. A prominent, triangular cape stretches out from the crater rim towards the southeast, to a distance of 30 km.

Montes Archimedes 25.3°N, 4.6°W

Montes Archimedes is a range of mountains that covers an area of about 160 × 140 km. The mountains directly adjoin the southern wall of Archimedes and, from there, run out in a southerly direction. They are a portion of the original inner wall of the Imbrium Basin, which had been heaped up to such a height that they were not submerged by the Imbrium lava.

Montes Caucasus

38.4°N, 10.0°E

The Caucasus is a ruggedly craggy, heavily eroded, extensive mountain range, and the direct continuation of the Apennines, separated from the latter by an approximately 50 km wide, flat, lava-flooded ‘strait’. The range stretches over a total length of approximately 520 km, and contains the highest peaks on the nearside of the Moon, which tower more than 6 km above the lava surface. To the east lies Mare Serenitatis, and to the west, Mare Imbrium. If one were a tourist standing on one of the highest mountains, one would be able to see for about 140 km.

Calippus 38.9°N, 10.7°E

A 32-km crater in the Caucusus highlands. The eastern crater wall runs almost in a straight line in the north-south direction. The western wall exhibits massive landslides. Very large instruments show a few crater pits on the crater floor. Calippus C, lying to the west, is a semicircular crater, 40 km in diameter, open to Mare Imbrium.

Rima Calippus 37.0°N,13.0°E

A fairly wide, slightly curved rille, 40 km long, southeast of Calippus. It lies on the northwestern edge of Mare Serenitatis.

Alexander 40.3°N, 13.5°E

Alexander is a very heavily eroded complex crater, 81 km in diameter. The northeastern wall of the crater has been almost completely destroyed.

Valentine Dome 31.0°N, 10.3°E

At the southern end of the Caucasus and lying to the east, is a large, almost circular plateau, which is interpreted as being a volcanic megadome. Officially, the feature remains unnamed, but in lunar literature has the nickname ‘Valentine Dome’.

Sinus Iridum 45.0°N, 32.0°W

Sinus Iridum, the ‘Bay of Rainbows’, is the most striking landmark in the northwestern portion of Mare Imbrium. It is the remnant of a giant crater, bordered on the northwest by the Montes Jura (the Jura Mountains), which are undoubtedly a portion of the original crater wall. On the lunar timescale, Sinus Iridum was formed after the Imbrium impact, but before the various lava flows flooded the Imbrium Basin. Sinus Iridum is about 260 kilometres in diameter, and so may be classified one of the smaller impact basins.

The Jura Mountains end in two capes; in the southwest lies Promontorium Heraclides with a height of 1.7 km, and in the southeast lies Promontorium Laplace, which reaches a height of 2.6 km above the average level of the surrounding surface. At sunrise, Promontorium Laplace casts a triangular shadow, and in larger telescopes a lunar dome becomes visible to the west. Other, difficult to observe, domes line near Promontorium Heraclides. They are, however, only observable under extreme grazing illumination. The lava plain within Sinus Iridum is not broken by any large craters. Large telescopes do, however, reveal a series of craterlets and crater pits on the lava surface.

If the northwestern wall of Sinus Iridum is examined more closely, it will be realized that the height of the wall on the eastern side as far as Cape Laplace is approximately the same height, whereas on the west, towards Cape Heraclides it continuously lowers.

Montes Apenninus 18.9°N, 3.7°W

The Apennines are the greatest range of mountains on the Moon's nearside. The name was first used by the Polish astronomer and lunar observer Hevelius (1611–1687). Like the Alps, the Apennines are the remnants of the rim of the Imbrium Basin that have not been flooded by lava.

The Apennines stretch for a total length of about 600 km and individual mountain peaks reach heights of 5 km. The slopes towards the Mare Imbrium are relatively steep at inclinations of about 30°, whereas on the opposite side, towards the Mare Vaporum (‘Sea of Vapours’) and Sinus Aestuum (‘Bay of Billows’) they are significantly less. The Apennine hinterland probably consists largely of ejecta from the Imbrium impact. When illuminated at Full Moon, the Apennines appear very bright.

Palus Putredinis 26.5°N, 0.0°

Palus Putredinis (‘Swamp of Decay’) is an irregularly shaped lava surface with an east-west extent of about 160 km, lying between Rima Hadley and the crater Archimedes. A nameless volcanic dome and a striking, thick lava flow may be seen south of the ghost crater Spurr (13 km, 27.9°N, 1.2°W).

Conon 21.6°N, 2.0°0

Conon is a very prominent crater, with a diameter of 21 km, with a sharp crater rim, lying behind the Apennines. It is possibly the result of a secondary impact caused by the main Imbrium impact.

Aristoteles 50.2°N, 17.4°E

A very prominent, young, large crater with a diameter of 87 km, which was probably created during the Eratosthenian period on the lunar timescale. Aristoteles has pronounced terraced inner crater walls, and the crater floor lies 3.3 km below the crater rim. Remnants of central mountains are detectable. The crater floor is relatively smooth and is divided, in a north-south direction by a flat ridge (only visible under grazing illumination). Beneath the western wall of the crater, a landslide is clearly visible. A small crater chain lies on the southern wall and the eastern wall has been overlain by Mitchell (49.7°N, 20.2°E), a crater 30 km in diameter. Mitchell's crater floor is slightly convex. As with the crater Aristillus, Aristoteles is also surrounded by a broad, circular zone of melted impact material.

Eudoxus 44.3°N, 16.3°E

Eudoxus is another prominent crater with terraced crater walls. It has a diameter of 67 km and a depth of 3.4 km. The floor of the crater, when compared with that of Aristoteles, appear significantly rougher. Both craters form a very conspicuous pair in the northeastern quadrant of the Moon.

Egede 48.7°N, 10.6°E

A crater, 37 km in diameter, that is almost completely filled with lava, with a somewhat angular shape, lying west of Aristoteles and Eudoxus. On the middle of the southern wall there is a crater pit, as there is on the northwestern portion of the crater floor. Large telescopes reveal about a dozen pits (between about 1 and 2 km in diameter) on the southwestern crater floor.

Montes Taurus 28.4°N, 41.1°E

The Taurus Mountains is a mountainous region east of Mare Serenitatis, extending for about 200 km. The highest peaks reach 3 km in height. The region has no clear boundaries and lies between Sinus Amoris (the ‘Bay of Love’) and Lacus Somniorum (‘Lake of Dreams’). The conspicuous crater Römer lies within the mountains. West of Römer, and running towards the south for 110 km, are the linear rilles Rimae Römer. North of Römer there is the rille system Rimae Römer G. Both systems of rilles are clearly visible under low illumination and are observable in small telescopes.

Römer 25.4°N, 36.4°E

A conspicuous crater in the southern Taurus Mountains with a diameter of 40 km, a sharp rim, terraced inner walls and a central peak running north-south. There is a small crater on the northern crater wall.

Littrow 21.5°N, 31.4°E

A lava-flooded crater, 30 km in diameter. The crater rim is flat, eroded and, towards the south, practically non-existent. Nearby, on the west, lying between Littrow and the small crater Clerke (7 km, 21.7°N, 29.8°E) are the arcuate, Rimae Littrow rilles, with an overall length of 120 km. North of Clerke is Catena Littrow, a short chain of small craters.

Gardner 17.7°N, 33.8°E

A smaller crater, 18 km in diameter, with a smooth floor. It lies on a domed plateau, which may probably be classed as a mega dome. The plateau's shape is like that of a peninsula, and is crossed by narrow rilles, chains of hills and rocky ridges.

Mare Vaporum 13.0°N, 3.5°E

Mare Vaporum (‘Sea of Vapours’) has an irregular, rounded shape with a diameter of 240 km and a lava-covered surface that amounts to about 55 000 km2. Mare Vaporum lies to the southeast of the Apennine mountains. In the south, Mare Vaporum merges, without any visible boundary, into the lava plain that is Sinus Medii. The southwestern and southeastern boundaries between Mare Vaporum and the highland regions are marked by secondary impacts from the great Imbrium impact (forming part of the Imbrium Sculpture). To the northwest lie Sinus Fidei and Lacus Felicitatis on the borders with the Apennine mountains.

Lacus Felicitatis 19.0°N, 5.0°E

Lacus Felicitatis (‘Lake of Happiness’) is a smaller, irregularly shaped lava area of only about 90 km in extent. It lies southeast of the crater Conon and east of Rima Conon. Scientists believe that they have found evidence here that part of this area still exhibits volcanic activity in the form of outgassing. Proof came in 2006 from a small area, named Ina, that lies on the southeastern edge of Lacus Felicitatis. Ina is a semicircular depression (shaped somewhat like the heel of a shoe), whose coordinates are 18.6°N, 5.3°E, and with a diameter of only about 3 km (about 1.5 arcseconds) and a depth of about 30 m. Even in large amateur telescopes the area is only partially visible.

Menelaus 16.3°N, 16.0°E

Menelaus is another young, very prominent crater, 26 km in diameter, with a sharp crater rim and central peaks.

Maurolycus 42.0°S,14.0°E

Faraday 42.4°S, 8.7°E

Stöfler 41.1°S, 6.0°E

These three craters form an impressive triplet for any size of instrument. Maurolycus and Stöfler were classed, on old Moon maps, as walled plains because of their size, and Faraday as a crater. The whole region around these craters in the southern highlands shows how violently and chaotically the Late Heavy Bombardment (LHB), more than 4 billion years ago, restructured the landscape through numerous impacts following one another in time, and superimposed on one another in space.

Maurolycus is an enormous complex crater with a diameter of 114 km, terraced inner walls and a central peak. The crest of the wall lies about 4.7 km above the crater's floor. The extent of the shadows shows that Naurolycus is the deepest of the three craters. The northwestern crater wall has been breached by Maurolycus F, and on the crater's floor there are the smaller craters Maurolycus M, J and A.

Faraday, probably the youngest of the three craters has a diameter of 69 km and a wall height of about 4 km. It lies in the centre of the three craters. The crater wall has been breached by three large, conspicuous craters, with Faraday A on the northeastern wall, and Faraday P and C on the southwestern wall.

Stöfler is a very large complex crater, with a diameter of 126 km and a depth of 2.7 km. Visual observations show a few small craters on the crater's floor, but large instruments reveal dozens of craterlets and pits.

Atlas 46.7°N, 44.4°E

The crater Atlas, with a diameter of 87 km, is a conspicuous example of the class of Fractured Floor Craters (FFC). This is shown by an extensive system of rilles on the floor of the crater. Posidonius and Gassendi are other striking examples.

Atlas has strongly terraced, inner crater walls, which rise 3 km above the crater's floor. The tip of a central peak is visible and the floor of the crater is rough and fissured. The rille system, Rima Atlas, is of volcanic origin (as will all craters of this type), and under high illumination, at least two dark spots are visible on the crater floor (as in the crater Alphonsus). The dark spots probably consist of pyroclastic ash deposits and suggest volcanic activity occurred a long time after the actual impact.

Hercules

46.7°N, 39.1°E

Hercules has a diameter of 69 km and, like Atlas, displays terraced inner crater walls. In contrast to Atlas, however, the crater's floor is flat, smooth and shows – just visible – the tip of a central peak. In addition, the floor of the crater has been flooded by lava. Directly south of the central peak is Hercules G (13 km). A further small crater, Hercules E (9 km) breaches the southern crater wall. Atlas and Hercules form a striking pair of craters on the Moon's northeastern limb.

Mare Humorum 24.0°S, 39.0°W

Like all the other lunar maria Mare Humorum (‘Sea of Humours’) is also an impact basin flooded in the centre with mantle lava. With a diameter of about 380 km (that is, of the lava-covered area: the actual basin is larger), it is one of the smaller maria, and is roughly comparable with Iceland in area. The Humorum Basin is also associated with a gravitational anomaly (a mascon).

The formation of the basin has been dated to the Nectarian period, approximately 3.9 to 3.8 billions years ago. Flooding with lava occurred much later. The lava layer is over 3 km thick in the central region. After the lava cooled and with the cessation of the pressure from the lava rising from the mantle, the lava layers collapsed under their own enormous weight and deformed the lunar crust beneath, thus creating the mare wrinkle ridges, fracture zones and escarpments around the edge of the basin. When the lava surface sank, previously existing craters and crater floors around the edge of Mare Humorum were therefore tilted in the direction of the centre. An area of Dark Mantle Deposit (DMD) lies on the floor of the mare, with deposits of dark, glassy, volcanic ashes, and which is crossed by a rille, whose origin is uncertain.

Mare Imbrium 30.0°N, 20.0°W

Mare Imbrium, the ‘Sea of Showers’ (named by Riccioli) is the dominant feature of the northwestern quadrant of the Moon. With an area of c. 830 000 km2, it is – after Oceanus Procellarum – the second largest mare area on the Moon. Like all the other maria it is the lava-filled central portion of a giant impact basin, 1200 km in diameter.

The mountain range of the Alps, Caucasus, Apennines and Carpathians are the remnants of the outer basin ramparts. Remnants of the inner ramparts are the mountain chains Montes Recti, Montes Spitzbergen, Montes Teneriffe and Mons Pico. Towards the west, in the direction of Oceanus Procellarum, there are no visible signs of the basin walls. Many of the isolated mountain massifs, including those along the norther boundary of Mare Imbrium, and Mons Delisle, are the remnants of former highland regions.

The impact that created the basin was so strong that traces of secondary events are still – even after 3.8 billion years – strikingly visible over the whole of the Moon's nearside. These traces have become known as the Imbrium Sculpture. Particularly strikingly visible are the traces of the Imbrium impact in the trio of craters Ptolemaeus, Alphonsus and Arzachel, and in the area around the crater Julius Caesar. The impacting body probably came from a northwesterly direction.

If the Imbrium Basin is observed when the terminator has passed roughly the centre of the Mare, and thus when the Moon's age is about 8.5 days, it is possible to see the boundary between the second of three lava flows that flooded the Imbrium Basin.

Pitatus 29.9°S, 13.5°W

Pitatus is a large, very interesting lava-flooded complex crater with a diameter of 106 km. Pitatus belongs to the group of FFC craters that includes craters such as Gassendi and Posidonius. Rimae Pitatus extend in a circular fashion, partially interrupted but almost complete around the inner wall of the crater. Additional sections also cross the crater's floor both in east-west and north-south directions. The bright patches on the floor consist of ejected material from the Tycho impact.

Hesiodus 29.4°S, 16.3°W

Hesiodus is directly bordering Pitatus on the west. It is a lava-flooded crater, about 42 km in diameter. Almost in the centre of the crater's floor lies the small crater Hesiodus D (5 km), with another crater pit directly east of it. The southwestern wall is overlapped by Hesiodus A (15 km). Hesiodus A is, like the crater Marth, a rare example of a crater with a concentric double wall (a double-walled crater).

At local sunrise (waxing Moon), Pitatus and Hesiodus offer a particular spectacle for observation. Between the crater walls of Pitatus and Hesiodus there is a valley-like structure. Because Pitatus lies farther to the east, the Sun rises slightly earlier for this crater. If the geometrical conditions are favourable (the positions of the Sun, Earth and Moon), sunlight falls through the valley between the crater walls and illuminates – like the beam of light from a searchlight – part of the crater floor of Hesiodus, otherwise still hidden in the lunar night.