What optical device is the Dutch scientist, after whom the lunar crater Jansen is named, credited for?
Jansen (crater) Jansen is a lunar crater in the north part of the Mare Tranquillitatis, named after Zacharias Janssen. It is located to the east-southeast of the crater Plinius. The rim of Jansen is low and narrow, with a notch along the western edge. The interior is relatively level, which may indicate it has been covered by lava. To the south-southwest a small but prominent crater lies on the crater floor, halfway between the center and the rim, further southeast is a small but prominent crater named Sinas.
Bunsen (crater) Bunsen is a lunar crater that lies near the northwestern limb of the Moon. It is located to the west of the Oceanus Procellarum and the crater von Braun. To the southeast is the crater Lavoisier, and to the northeast lies Gerard. Northwest of Bunsen, on the far side of the Moon, is McLaughlin. Due to its position this crater appears foreshortened when viewed from the Earth, and its visibility is affected by libration.