The observations of the 
CO(1 
0) line were made in 1989 May,
June and October, 1990 January July, and 1991 May, using the SEST,
located on La Silla, Chile, at an altitude of 2200 m. At 2.6 mm
the antenna HPBW is 43''.
The receiver was a single channel cooled Schottky mixer, tuned to
be optimized as a single sideband receiver. The effective system
temperature on the sky, 
(corrected for rearward spillover and
atmospheric attenuation) was typically 
. Spectral
resolution was provided by a 2000 channel AOS with a resolution of
43 kHz/channel. Observations were made in a frequency switching
mode, with a throw of 15 or 20 MHz, depending on the velocity
range over which emission was seen. The line was always in the
spectrometer bandpass for both halves of the switching cycle. The
15 MHz shift for frequency switching corresponds to 39 km s
, so we
could have seen emission approximately 30 km s
on either side of
the center velocity. Spectra were folded in the final processing
to improve the rms by 
. Most of the spectra required the
removal of third order baselines in the final processing. This
could be done reliably because the lines are relatively narrow,
and we have a large number of channels to determine the baseline
accurately. For the reduction of the data, groups of five
adjacent channels were averaged to provide an effective resolution
of 215 kHz, corresponding to a velocity resolution of 0.55 km s
.
Intensity calibration was performed using the chopper technique,
in which the receiver alternately looks at the sky and an ambient
temperature absorber during the calibration phase. The time
between calibrations was typically 10 to 30 minutes, depending on
elevation and sky stability. The intensities are reported as 
(Kutner & Ulich 1981), in which the intensities are corrected
for atmospheric attenuation and rearward spillover. To convert to
, one must divide 
by the forward spillover and scattering
efficiency, 
. This value was determined from
observations of the Moon. To convert to 
the brightness
temperature for a source that uniformly fills the main beam, one
must divide 
by the product of 
and source coupling
efficiency for an object that uniformly fills the main beam, 
for the SEST. This means that 
. Unless
otherwise stated, contour maps and spectra are presented on the 
scale. Tabulated properties, such as peak temperature or
integrated intensity, as well as derived quantities, such as CO
luminosities, will be presented on the 
scale, since we are
talking about objects for which there is some idea of the extent
relative to the beam size. To convert those values back to 
they
should be multiplied by 0.74, and convert back to 
they should
be multiplied by 0.80.
Pointing was checked periodically on the SiO maser, R Dor, which is near the LMC in the sky. This allowed pointing checks in the same azimuth and elevation range as the source. The rms pointing errors were typically 4'' in each axis.
The general observing philosophy for the Key Programme was to
produce fully sampled maps. For 
CO(1 
0) , this means a grid
spacing of 20'' (or 5 pc at the LMC distance). Integration times
were adjusted to provide an rms noise level in the final (folded
and frequency degraded) spectra of 0.10 K (on the 
scale).
Typical integration time per map position were approximately 4
minutes under the best conditions.
As mentioned above, the regions studied here were chosen on the
basis of fully sampled observations of a strip, partially shown
in Fig. 1 (click here). That strip is at 
with
ranging from -68
45' 00'' to -72
00' 00''.
Of the 585 positions in the strip, emission
above our threshold was found in 88 (
of the) positions. The
detections were also concentrated in a way that suggested that the
strip was cutting through clouds with large gaps in between. The
clouds thus found in the strip were the ones selected for detailed
mapping.