We present spectrally resolved measurements of CO 4th positive radiation down to 170 nm under equilibrium conditions. The emission is calibrated in absolute intensity by using an argon discharge calibrated to NIST standards. The measurements were undertaken to validate radiation models available in the literature. NASA EAST measurements had noted a discrepancy between radiation model predictions and their shock tube measurements. Our goal was to perform these measurements under equilibrium conditions and compare against model predictions. To that end, we selected several datasets for the electronic transition moment available in the literature. These were used to calculate state-specific Einstein coefficients for use with the radiation code SPECAIR. Three datasets were tested and two were found to give good agreement with the experimental results.