Brighter Spectrographic Images by the Use of Anamorphic Optics

Abstract

A new method is proposed for increasing the light per unit area in a spectrographic image for a source of surface brightness (luminance) and for a given linear dispersion. An imaging system is used that has given a shorter effective focal length and a larger relative aperture in a plane parallel to the slit than in a plane containing the direction of dispersion. In favorable cases, twentyfold intensification would be possible. Relations are derived to enable the sizes and focal lengths of the components needed for one such system to be calculated simply in any particular case. The quality of the components required is not critical.