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.
Simon von Stampfer Simon Ritter von Stampfer (October 26, 1792 (according to other sources 1790), in Windisch-Mattrai, Archbishopric of Salzburg today called Matrei in Osttirol, Tyrol – November 10, 1864 in Vienna) was an Austrian mathematician, surveyor and inventor. His most famous invention is that of the stroboscopic disk which has a claim to be the first device to show moving images. Almost simultaneously similar devices were produced independently in Belgium (the phenakistiskop), and Britain (the zoetrope).