SIGMA observations of the galactic gamma-ray emission

Since September 1994 the GRANAT satellite has been almost continuously oper ated in the scanning mode, spinning with a period of 12 minutes around an a xis pointed roughly at Sun. During this phase of operation the SIGMA soft g amma ray telescope, having its main axis perpendicular to the spin axis, ha s been accumulating photons in four broad energy bands (40-600 keV) every 4 seconds. Knowing the angular response of the telescope we were able to rec onstruct the satellite attitude with satisfactory precision for those perio ds when at least one strong point source was visible. In the whole sky maps obtained in such a way we can clearly detect gamma-ray emission from the g alactic plane. In this paper we discuss the spatial distribution of this em ission and its spectral properties.