Milky Way emissivity ϵ_ν at high Galactic latitude. Left panel: we compare estimates obtained from COBE-DIRBE and Planck data of the south Galactic pole (Planck Collaboration Int. XVII 2014) and from IRAS, Herschel, and Planck data of the HeViCS fields (Bianchi et al. 2017) to those derived from the COBE-FIRAS spectrum. In the right panel, we show MBB fits to the HeViCS data (Bianchi et al. 2017) and to IRAS and Planck data over the whole diffuse high-Galactic latitude cirrus (Planck Collaboration XI 2014), together with the predictions from the THEMIS and Draine et al. (2007) dust models heated by the LISRF. The HeViCS data points are repeated to facilitate comparison.