improve the baseline quality, we used also the “Wobbler switching” mode with a 240 throw. We reached an r.m.s. sensitivity in main-beam brightness units of about 100 mK in all lines except (3-2) ($\sim$ 400 mK). The pointing was checked every 2 hours by means of a 3 or 2 mm continuum scan on nearby quasars and was accurate to within $\sim$ 4.

In order to refine the maps, originally taken with a 20  spacing, we observed in Nov. 2002 with a 10 grid (but 5 spacing in the inner 20 seconds).

[lccccc]{} line & frequency & HPBW & F$_{throw}$ &T$_{SYS}$ & $\Delta v_{res}$\
& GHz & & kHz & K & km s$^{-1}$\
(1-0) & 93.1737725 & 26 & 7.5 & 150 & 0.063\
(3-2) & 279.511385 & 9 & 14.3 & 1900 & 0.021\
(2-1) & 154.217137 & 16 & 7.5 & 370 & 0.038\
(3-2) & 231.321966 & 10 & 14.3 & 750 & 0.050\
(1-0) & 109.782160 & 22 & ... & 170 & 0.026\
(2-1) & 219.560319 & 11 & ... & 450 & 0.033\
(1-0) & 112.358988 & 21 & 7.5 & 230 & 0.026\
(2-1) & 224.714368 & 11 & 14.3 & 730 