Electrographic cameras for the vacuum ultraviolet

The advantages of electrographic cameras over conventional photography include higher speed, higher resolution, linearity of response, and photometric accuracy. In the vacuum ultraviolet photosurfaces, such as alkali halides, can be used which are not harmed by emulsion outgassing. The development of a series of magnetically focused electrographic cameras utilizing front-surface alkali-halide photocathodes is considered. In the devices, the photocathode is mounted at the focus of an optical system which is partially contained within the imaging device. An electrographic Schmidt camera is discussed along with all-reflecting spectrograph cameras, electrographic concave-grating spectrographs, and a direct-imagery electrographic camera for use with large telescopes.