Description and Technical Details . In 1980s two medium-size horizontal solar telescopes 50/35000 cm with large spectrographs Czerny-Turner made by Carl Zeiss Jena were installed in the Ondњejov observatory. The Czerny-Turner-spectrographs in the Ondњejov observatory called HSFA1 and HSFA2 according to the German name Horizontal-Sonnen-Forschungs-Anlage ("horizontal device for solar research") have been explored for more than two decades. ... Diffraction grating - Richardson, Spectra-Physics . ...