A Schmidt camera manufactured from a solid cylinder of glass, with the figuring performed on both ends. A hole is needed at the corrector end to position the film. With this system a focal ratio of f/0.35 is theoretically possible using glass, or even f/0.2 using diamond. However, the design is practicable only for small apertures, and suffers from chromatic aberration, making it suitable only for use with monochromatic light, such as in spectroscopy.
Subjects: Astronomy and Astrophysics.