This equipment destined to treat telescope mirrors of 2.5m diameter by ion polishing (ultimate polishing step). The work chamber volume presented below is 28 m3. The ion gun is installed at the extremity of a five axis robot. Function of the mirror defaults cartography, the ion sources stays more or less longtime on the different zones to abrade. With this technique we can obtained perfect surface state with a roughness around the nanometer. Reproducibility and the positioning precision of the ion source is the success key of this equipment.