Abstract: High-resolution spectrometer was designed to resolve the fine structure of discharge emitted radiation near hydrogenous line 4648.8 A. The device consists of two concave diffraction gratings with 2700 grooves per mm and the radius of curvature 1000 mm. Optical mounting is calculated in such a way that the second grating compensates aberration of the first one for one wavelength. Using slight nonequidistancy of grooves we reduce aberrations in narrow region near this wavelength and achieved limit of resolution about 0.015 A for the spectral region of interest: 464.18- 465.15 nm. Diffraction gratings for this spectrometer have been produced mechanically in Sate Vavilov Optical Institute, St. Petersburg, Russia, by EA Yakovlev. Gratings show good spectral and energetic characteristics at previous laboratory tests and will be used in spectrometer, which is under mounting now. Area of these gratings is limited by mechanical way of production. The limit size is 50 by 50 mm. To detect weak signals it could be good to increase the are of gratings. To do it we try to calculate optical mounting of recording of these gratings holography. Since classical method of recording using homocentric beams which go to the grating blank from the same side of it does not provide aberration compensation conditions, we calculated recording mounting using recording in opposite directed beams. !8
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