Spectral system of Offner imaging spectrometers with convex grating utilizes only three spherical and centred surfaces achieving anastigmat

small spectral and spatial distortion

compact size and large numerical aperture. Concentric alignment with high precision is the key to realize these advantage. Based on the principle of dual-beam monochromatic interference and concentric system

interferometrical optics alignment for Offner imaging spectrometers with convex grating is given.With this method

the primary and tertiary mirror of Offner imaging spectrometers achieve concentric

the convex grating is arranged according to reading spectrogram directly and concentric alignment with high precision is realized. By the result

interferometrical optics alignment can achieve the distance between centers of the primary and tertiary mirror of Offner imaging spectrometers several nanometer or near zero.