R Peg visibility data obtained in June 2016. The black lines denote the squared visibility amplitudes measured on the science camera. The errors are indicated by mean squared visibility amplitudes and their errors on each side of the plot for the first and second half of the wavelength interval. The red points with error bars denote the squared visibility amplitudes measured on the fringe tracker camera with low spectral resolution. The blue dots denote synthetic values based on UD fits at wavelengths of 2.05 μm (water), 2.25μm (near-continuum), 2.29 μm (CO 2-0), and 2.32 μm (CO 3-1). The green lines denote a fit of a CODEX model atmosphere with the parameters listed in Table 4.