EUV radiation is strongly absorbed by the Earth's atmosphere and by interstellar gas. Numerical simulations of the EUVITA telescopes on board the future Spectrum-X-G satellite show that this EUV instrument will be able to detect and derive physical parameters of several classes of astrophysical sources.

Simultaneous multi-wavelength observations of AGN, such as with Spectrum-X-G, are important for the study of their spectral components. Simultaneous UV and X-ray spectra of 8 Sy1 galaxies are analyzed. The maximum temperatures of the "blue bump" components are very similar in the sample, independent of luminosity and radio-loudness.

This result cannot be easily explained by current models of "blue bump" emission. Non-simultaneous optical, UV and X-ray data of radio-quiet QSO 0914-62 reveal typical Sy1 spectral properties. There is evidence for moderate continuum and line variability. A broad UV absorption line (CIV 1549Å) has been detected for the first time in this source