Two sections from K-band spectra of R Aqr. The dashed line is an out-of-eclipse 1989 spectrum. The solid line is the in-eclipse 2020 September spectrum. The spectra are shifted so the atomic lines appear at the rest frequency. The telluric spectrum has been removed by ratioing to synthetic reference spectra. ¹²C¹⁶O 2–0 and 3–1 lines are labeled. Large changes in the low-J lines (Figure 4) are apparent. For the other lines, for instance Na 4276 cm⁻¹ (top panel) and CO R83 and R81 (bottom panel), the in-eclipse lines are slightly less deep than the out-of-eclipse lines. To compare the scale of the abscissa to the line profiles to Figure 4, broad lines, for example 2–0 R4 and 2–0 R19, have widths of ∼0.5 cm⁻¹ corresponding to 35 km s⁻¹.