ESA Science & Technology - Crater Hopmann

This image, taken by the Advanced Moon Imaging Experiment (AMIE), shows one quarter of crater Hopmann - an impact structure about 88 kilometres in diameter, located on the far side of the Moon. The scene covers a square of about 39 kilometres per side. The hills on the lower left side are the crater wall of Hopmann.

The crater (centred at 50.8° South, 160.3° East) is situated on the edge of the giant South Pole-Aitken basin (SPA), the largest impact crater in the solar system with a diameter of 2500 kilometres and a depth of 13 kilometres. The SPA basin shows distinctive chemical composition with unusual mineralogy types, and possible exposure of rocks from the lower crust or the upper mantle.

The Hopmann crater is very old and many small craters can be seen on its flat floor, the larg one on the right in this image showing an interesting double-ringed structure.  The crater's outer rim has also been eroded by later impacts.

The small crater chains in the middle of the top half of the image can be interpreted as series of secondary craters, created by the impact of the material ejected from a nearby large impact. This ejected material flies away in molten state, and fall in large droplets. When these impact on the surface, they form typical crater chains as those visible in this image.

The crater is named after Josef  Hopmann (1890-1975), an astronomer that worked in Bonn, Leipzig and as Director of the Vienna Observatory.