The maps are projections of the full sky in Galactic coordinates. The plane of the Milky Way is horizontal in the middle of the map with the Galactic center at the center. Galactic longitude ﹩l=90^{\circ }﹩ is left of center. The maps are smoothed to 10° resolution. The black stripes are unobserved portions of sky. Color bars indicate emission intensity in units of nW m⁻² sr⁻¹. The scale is not linear. Top: A full sky map of 157.7 μm C II emission from the COBE FIRAS experiment. Bottom: A full sky map of 205.3 μm N II emission from the COBE FIRAS experiment.