Fig. 3From: Development of low-cost sky-scanning Fabry-Perot interferometers for airglow and auroral studiesPictures of the Fabry-Perot interferometers, (a) body of FP01, (b) 70-mmϕ etalon on the holder, (c) body of FP02, (d) controllers and a personal computer for FP01 at Tromsø, and (e) water circulation system for cooling the CCD camera.Back to article page