The spectrum and position of the hard galactic centre source 1E 1740.7-2942.

Observations of the remarkable hard Galactic center X-ray and gamma-ray source 1E1740.7 - 2942 made with the TTM and HEXE experiments of the Roentgen observatory on the Kvant module are presented. The spectrum can be well described by a hard power-law with a high-energy cutoff and absorption at low energies. Similarities to the spectra of Cyg X-1 and other black hole candidates suggest that 21E1740.7 - 2942 may also be a black hole binary. The position of this source has been determined with an uncertainty of 12 arcsec, a significant improvement on the precision of earlier measurements.