Jackson is an impact crater located in the northern hemisphere of the far side of the Moon. It is a 71 km dia crater at 22.4°N and 163.1°W (shown in the inset). The interesting feature at the western outer rim of Mach crater is another impact crater, Mitra (92 km dia). It is named after Prof. Sisir Kumar Mitra, who was an Indian physicist and Padma Bhushan recipient known for his pioneering work in the field of ionosphere and Radiophysics. The Korolev crater seen in the image is a 437 km crater which has several small craters of varying sizes. Sommerfeld is a large impact crater located in the farside northern latitudes of the Moon. It is a 169km dia crater at 65.2°N and 162.4°W. It has relatively flat interior surrounded by a ring mountain and a number of smaller craters lie along the rim edge. The crater is named after Dr. Arnold Sommerfeld who is a German physicist pioneered in the field of atomic and quantum physics. North east to this crater lies the Kirkwood crater named after the American astronomer Mr Daniel Kirkwood, another well-formed impact crater which is approximately 68 km dia.