.  An x-ray grating spectrometer was built in order to measure opacities in the 00 eV to 000 eV spectral range with an average spectral resolution ∼ 00. It has been used at the LULI-0000 laser facility at École Polytechnique (France) to measure the Δn = 0, n = 0 transitions of several elements with neighboring atomic number: Cr, Fe, Ni, and Cu in the same experimental conditions. Hence a spectrometer with a wide spectral range is required. This spectrometer features one line of sight looking through a heated sample at backlighter emission. It is outfitted with one toroidal condensing mirror and several flat mirrors cutting off higher energy photons. The spectral dispersion is obtained with a flatfield grating. Detection consists of a streak camera sensitive to soft x-ray radiation. Some experimental results showing the performance of this spectrometer are presented.  An x-ray grating spectrometer was built in order to measure opacities in the 00 eV to 000 eV spectral range with an average spectral resolution ∼ 00. It has been used at the LULI-0000 laser facility at École Polytechnique (France) to measure the Δn = 0, n = 0 transitions of several elements with neighboring atomic number: Cr, Fe, Ni, and Cu in the same experimental conditions. Hence a spectrometer with a wide spectral range is required. This spectrometer features one line of sight looking through a heated sample at backlighter emission. It is outfitted with one toroidal condensing mirror and several flat mirrors cutting off higher energy photons. The spectral dispersion is obtained with a flatfield grating. Detection consists of a streak camera sensitive to soft x-ray radiation. Some experimental results showing the performance of this spectrometer are presented.  An x-ray grating spectrometer was built in order to measure opacities in the 00 eV to 000 eV spectral range with an average spectral resolution 