42. Mollinger, Otto. Himmels-Atlas mit transparenten Sternen. Solothurn, 1851.
As the market for popular star atlases opened up, it was inevitable that gimmicks would appear, and Mollinger's Sky Atlas with Transparent Stars used an ingenious one, printing the star maps on cards, punching different sized holes at the star positions, and mounting the cards on transparent paper. So if you hold one of these cards up to a bright light in a dark room, you will see the stars, it was argued, as they appear in the sky. Unfortunately, the light has to be so bright that if you then look at the real night sky, you will not be able to see a thing. Nevertheless, the charts are attractively printed and function quite well under ordinary light. We see a detail of the region of Andromdea and Perseus here.