Possibly invented by Athanasius Kircher (1602-1680) and a precursor to pre-digital 20th century slide projectors that used 35 mm slides, the projector Lord Asriel requests was once called a magic lantern. A reflector and lens focused light on a glass slide; oil (naptha in Lyra’s world) provided the source of light.
In the 2007 10th anniversary editions of His Dark Materials include what Pullman calls “lantern slides,” ideas or images that came to mind after the books’ initial publication. He uses this term because they remind him of his grandfather’s collection of painted slides for storytelling, a way-back precursor to film.
Athanasius Kircher makes an appearance in Lyra’s Oxford in an ad as the author of Polymathestatos: A Festschrift in Honour of Jocelyn Godwin.
The magic lantern image is from Giorgio de Sepibus, Romani Collegii Musaeum Celeberrimum, p. 39, and is among the Athanasius Kircher ((1602-1680)) collections and research activities at Stanford University. Public domain.