Optical emission measurements of CO 4th positive radiation, calibrated in absolute intensity, are compared with SPECAIR calculations done using the electronic transition moment function (ETMF) of Spielfiedel and Kirby and Cooper. The emission measurements are spectrally resolved and span the VUV and UV spectral regions, with a minimum reported wavelength of approximately 140 nm. The source for the CO 4th positive emission is an atmospheric plasma produced using an inductively coupled plasma torch facility. A mixture of CO2 and Ar is injected and heated via the induction fields to produce the hot CO responsible for the observed 4th positive emission. The comparison between experimental measurements and SPECAIR calculations shows that the ETMF used reproduces well the observed emission.