A zoom of the RGS 1 and 2 spectra of 4U1700+24 around the O VIII Ly-α emission line (at about ≃19 Å) for all the observations quoted in Table 1. The spectra were binned in order to have a signal-to-noise ratio of 5 in each bin, and we give the horizontal axis in energy instead of wavelength. The data in yellow/orange (corresponding to the 2002 observation, i.e. 0155960601) clearly show a large continuum component with respect to the other data sets, thus reflecting the high activity of the source at that time. The solid lines represent the best-fit model as described in the text.