Computer for the Abel Inversion

Abstract

An electronic analog‐type computer is described which performs the Abel inversion on signals detected by a scanning photoelectric spectrometer. This computation is necessary to obtain the radial characteristics of an inhomogeneous light source from the observed ``side‐on'' measurements. The amplitudes resulting from a Fourier analysis of the photomultiplier signal are operated upon to produce an electrical signal corresponding to the source intensity at any desired radial distance. This signal can be continuously recorded as a function of wavelength. The optical system used for repetitively presenting the intensity profile of the source to the computer at 100 cps is also described.