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This paper describes diffractometric and interferometric installations for monitoring the optical homogeneity of materials in the mid-and far-IR regions. It gives the results of a calculation of the errors of optical homogeneity measurements by various methods. The results of measuring the optical homogeneity of large blanks made from optical crystals in the IR region are presented.

The results of new alignment technique for a telescope with the Epps-Shulte focus are presented. The technique is based on application of the synthesized holographic elements and IR interferometry.

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The automated diffraction mterferometer with scatter plate (DISP)It is described. Special feature of the mterferometer optical scheme is a special construction of an illuminator which permits to suppress speckle structure of interferometric picture. The basic part of the illuminator is a vibrating fiber bundle made from multimode optical fibers different lengths.The difference in fiber lengths overcomes the coherent length of multimode laser used as a radiation source in the interferometer. Mathematical model of DISP is presented. Mathematical model of DISP interferogram was derived from refmed calculation of ray path. The model allows to evaluate errors of measurement in relation to parameters of a detail under control and size of scatter plate. It is shown that the fmite size of scatter plate causes an additional phase shift. This additional phase shift we can be considered as a DISP systematic error. The procedure for calibration of DISP instrumental error is proposed. It is based on the analysis of an interferogram set made from the only optical detail under different orientation about interferometer optical axis. Experimental data on DISP error calibration is presented. DISP root mean square error is not over O.OO52 for detail under control with relative aperture 1 :7. The production procedure of a scatter plate with uniform high aperture scattering indicatrix is described. It is based on photoregistration of coherent radiation scattered on round diffuser with central obscuration. The obscuration is performed by transparency with inverse Gauss function transmission.