Franck 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...

 impact 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 lies near the north end of 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 on the northern part of 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...

. The crater lies just to the southeast of Brewster

Brewster (crater)

Brewster is a small lunar impact crater in the northern fringes of Sinus Amoris. It lies to the southwest of the larger crater Römer. To the southeast of Brewster is the similar-sized Franck. This crater is cup-shaped and symmetrical, with no overlapping craters of note. A low ridge is attached to...

, and farther to the south of Römer

Römer (crater)

Römer is a lunar impact crater that is located to the north of the Sinus Amoris in the northeast section of the Moon. It lies in the southwestern part of the mountainous region named the Montes Taurus. To the west-northwest is the crater-bay Le Monnier, on the eastern edge of Mare Serenitatis.The...

. Franck was previously designated Römer K before being given a unique name by the IAU

International Astronomical Union

The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...

.

This is a circular, bowl-shaped crater with a sharp rim that has not been significantly eroded. The interior walls slope down to the tiny floor at the mid-point. Just to the north of Franck is a joined pair of smaller craters, and the three nearly form a merged cluster of impacts.