 In his 1613 book "Opticorum Libri Sex" Belgian Jesuit mathematician, physicist, and architect François d'Aguilon described how some charlatans cheated people out of their money by claiming they knew necromancy and would raise the specters of the devil from hell to show them to the audience inside a dark room.The image of an assistant with a devil's mask was projected through a lens into the dark room, scaring the uneducated spectators.By 1620 Kepler used a portable camera obscura tent with a modified telescope to draw landscapes.