Abstract: The Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) Soft X-ray Imager (SXI) will shine a spotlight on magnetopause dynamics during magnetic reconnection. We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time. By making assumptions about the magnetopause shape, we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic (MHD) simulation. The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 R_E (Earth radius) and the maximal difference equals 0.24 R_E during the 25-minute interval around the southward turning.