Data reduction process for the LABOCA campaigns. All maps are zoomed to the innermost 3.5′× 3.5′. Left: a single measurement map of the GC from 2009-05-17T04:19:58. Center: model of the extended submm emission from the GC: co-added maps with subtracted point source at the position of Sgr A*. Right: remaining map for the 2009-05-17T04:19:58 map after subtraction of the GC model for the extended emission. The point like source represents the submm emission from Sgr A* itself.