An instrument is described that poduces monochromatic images differing from normal fiitergrams in that the wavelength of the transmission band varies slowly and linearly across the image. The monochromatic bandwidth can be changed to almost any value, and the transmission band can easily be shifted to any part of the visible spectrum. Various applications for solar research are discussed.
J. O. Stenflo, "Solar Chromatograph," Appl. Opt. 12, 805-809 (1973)