Abstract: The telescope includes at least one primary concave mirror (MI) for receiving an incoming image and relay optics for enlarging the image reflected by the primary mirror. The relay optics comprise a secondary mirror (M2) and a tertiary mirror (M3), each having a central aperture (12, 13) and each being positioned coaxially with the primary mirror (M1). The secondary mirror (M2) receives the image reflected by the primary mirror (M1) through the central aperture (13) of the tertiary mirror (M3). The tertiary mirror (M3), positioned close to the focal plane of the primary mirror (M1), receives the image reflected by the secondary mirror (M2) and reflects that image through the central aperture of the secondary mirror (M2).

Abstract: The cooling device for cooling a travelling-wave tube is deigned to be mounted on board a geostationary telecommunications satellite. The collector of the tube is thermally insulated from the remainder of the tube and it is thermally connected to a radiator by means of a link part passing through a north or a south panel of the satellite structure and insulated from the panel.