Extinction map of Cha I derived from 2MASS in radio projection. The projection center is at (α,δ)_J2000 = (11^h01^m24^s,  −77°15′00″). The contours start at A_V = 3 mag and increase by step of 3 mag. The dotted lines are lines of constant right ascension. The angular resolution of the map (HPBW = 3′) is shown in the upper right corner. The four fields selected for mapping with LABOCA are delimited with dashed lines and their center is marked with a black cross. The white plus symbols in fields Cha-Center and Cha-North mark the positions of the dense cores Cha-MMS1 and Cha-MMS2, respectively, detected in dust continuum emission at 1.3 mm with the SEST (Reipurth et al. 1996). The field of view of LABOCA is displayed in the lower right corner.