Notes.For each transition (indicated in the fourth column) we listed the wavenumber ν, the Doppler shifted wavenumber ν_D and the corresponding measured flux (at the top of the atmosphere). Modeled line g-factors at 1 AU from the Sun and retrieved line production rates Q_line, with the relative errors, are given in the fifth and sixth columns respectively. In the last column the values of the terrestrial atmospheric transmittance are shown. Values of g-factors are given for the “null slope” rotational temperatures of 53 K for 8P, and 66 K for C/2007 W1. With confidence limits, the retrieved values are 53 ± 2 K and 66 K, respectively. We assumed T_rot = 60 K for C/2008 Q3. The B letter in the fourth column indicates if a detected HCN emission line is blended with emission lines coming from other molecules; for comet C/2007 W1 the line production rate relative to the R6 transition was much different from the other values (could it be that this line is blended with a line from an unknown species) and thus was not considered in the computation of production rate and rotational temperature.