Franz is a small 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...

 that is located along the eastern edge of the Sinus Amoris

Sinus Amoris

Sinus Amoris extends northward from the northeast end of the Mare Tranquillitatis. It is located at selenographic coordinates 18.1° N, 39.1° E, and lies within a diameter of 130 km. To the north of the bay are the jumbled Montes Taurus peaks.Near the southern end of the bay where it outlets...

, a bay that forms a northern extension to the Mare Tranquillitatis

Mare Tranquillitatis

Mare Tranquillitatis is a lunar mare that sits within the Tranquillitatis basin on the Moon. The mare material within the basin consists of basalt formed in the intermediate to young age group of the Upper Imbrian epoch. The surrounding mountains are thought to be of the Lower Imbrian epoch, but...

. It lies to the southwest of the prominent crater Macrobius

Macrobius (crater)

Macrobius is a prominent lunar impact crater located to the northwest of the Mare Crisium. It lies on the southeast edge of the Lacus Bonitatis, a small lunar mare. The somewhat smaller crater Tisserand lies just to the east....

. To the north is the smaller Carmichael

Carmichael (crater)

Carmichael is a lunar impact crater that is located along the eastern edge of the Sinus Amoris, in the northeastern quadrant of the Moon's near side. It lies within a couple of crater diameters south-southwest of the smaller crater Hill. Further to the east-northeast is the prominent crater Macrobius...

, and to the northwest is the diminutive Theophrastus

Theophrastus (crater)

Theophrastus is a small lunar impact crater at the southern part of the Sinus Amoris, a bay at the northeast part of the Mare Tranquillitatis. It lies to the southeast of the lava-flooded crater Maraldi, and was designated Maraldi M until the IAU gave it its current name...

.

The rim of this crater has been eroded due to subsequent impacts, although it retains a generally circular form. The interior has been flooded, leaving only a narrow inner wall and a low surviving rim. This floor has the same albedo

Albedo

Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...

 as the surrounding terrain, and is not as dark as the lunar mare

Lunar mare

The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...

 surface to the north and west. Attached to the exterior of the eastern rim is Proclus E, a merged double-crater formation. Proclus

Proclus (crater)

Proclus is a young lunar impact crater located to the west of the Mare Crisium, on the east shore of the Palus Somni. It lies to the south of the prominent, terraced crater Macrobius, and west-northwest of the lava-flooded Yerkes...

 lies to the east across the Palus Somni

Palus Somni

Palus Somni is an area on the Moon of relatively level but somewhat uneven terrain that lies along the northeastern edge of Mare Tranquillitatis and the Sinus Concordiae. It has selenographic coordinates 14.1° N, 45.0° E, and has a diameter of 143 km.The surface of this feature has low ridges and...

, or Marsh of Sleep.