A Spatial Spectral Scanning Technique for the Fabry–Perot Spectrometer

A technique is described whereby wavelength scanning of a Fabry–Perot spectrometer is accomplished by varying the angle at which light is transmitted through the etalon. It is in essence a simple photoelectric adaptation of the old photographic method but it has a number of important advantages. These are pointed out, and descriptions are given of four instruments in which the technique has been applied. One of these instruments is hypothetical, one is under construction, and two have been built and tested. They are all designed primarily for auroral and airglow observations, but the method should find use in studies where the source is either of low brightness or of short-lived duration. Because one can employ a solid etalon, the technique may also be useful in rocket and satellite instrumentation.