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.
Florey (crater) Florey is a lunar impact crater on the lunar near side near the northern pole. Florey is directly adjacent to Byrd crater (diameter of 94 km) to the Southeast and Peary crater (diameter of 73 km) to the North. The crater is named after Australian scientist Howard Florey. The crater was named by the IAU in 2009.