Comparison of S/N variations for a planet with temperature of 1700 K with (bottom panel), and without (top panel) telluric absorption. The telluric absorption spectrum has been computed for an airmass of 1 using the ESO Skycalc module. The telluric absorptions do not impact the S/N distribution very much, with the exception of making it slightly more sensitive to the central wavelength, thus delimiting the spectral domains of interest more clearly. For instance, we see that near 2 µm the tellurics separate more the two zones of interest in H band and in K band by making the S/N vary more quickly.