Clavius

My last stop was much further south at the huge crater Clavius just below Tycho. At 225km diameter Clavius is one of the largest impact craters on the Moon.


Clavius is a relatively old crater having been formed around 4 billion years ago. Despite its age Clavius is well preserved but has numerous other impact craters on the crater floor. Starting from Rutherford on the southern rim, Clavius D, C, N, J and JA form an anti-clockwise arc across the crater floor. The decreasing size of these craters means they are often used to test the resolution of amateur telescopes. Clavius JA doesn't show up well in this photo but is usually quite clear if I use a Barlow lense. The other craters on the rim are Porter (north-east), Clavius L (west) and Clavius K (south-west).

In contrast Tycho, visible in shadow to the north-west of Clavius, is a very young crater around 100 million years old. There is speculation that Tycho was formed by an impactor from the same family of asteroids that produced the impactor that caused the extinction of the dinosaurs on Earth.

For completeness the crater on the terminator south-west of Clavius is Blancanus; the large crater to the north-east is Maginus; and the crater in the south-east with the prominent central peak is Moretus.