Tycho 43.4°S, 11.1°W

Tycho is, with Clavius, undoubtedly the most prominent crater in the southern highlands. Its outer diameter amounts to 102 km and the inner crater wall measures about 85 km in diameter. It exhibits marked terraces on its interior walls and a complex central peak, which appears, from Earth, angular, steep and furrowed. The crater's walls reach a height of 4.8 km above the floor and the central peak towers 2.3 km above that floor.

Under high illumination, Tycho exhibits the largest and brightest of all ray systems. Tycho is certainly one of the youngest lunar craters, probably created only about 100 million years ago. Portions of the ray system may be traced over a distance of 1800 km. The most conspicuous and brightest rays stretch towards the east (Stöfler), southwest (Longomontanus, Clavius) and northwest (Kies, Bullialdus). The ray system is so bright that it is even visible by earthshine. Shortly after First Quarter, Tycho appears like a black chasm, surrounded by thick walls.

Under grazing illumination it becomes obvious that the crater is surrounded by a ring zone of dark material with a diameter of about 150 km. It consists of lunar crust that was melted by the energy of the impact and has subsequently solified.