The flatfields must be done once per pool session. This observations must be carried out during nights only under very stable weather conditions (tau of 0.5 is ok though). If the conditions are not such stable the flatfield should be redone.

Low tau is not so important, but stable pointing is.

In case MAMBO2 or the mirrors in front of it are readjusted, several flatfields must be done several times.

If not suitable planets are up during the night a strong (10Jy/beam) point source somewhere between 50 and 70 deg (e.g. J1229+021). The source should be point-like (e.g. Uranus and Mars, but not Saturn or Jupiter!).

In detail, the rcpmap procedure is:

The duration of this map is (290/5)*360 ~ 1hr.