Astrophysical objects observed by the MESSENGER X-ray spectrometer during Mercury flybys

► We model MESSENGER spacecraft attitude during flybys of Mercury. ► We predict X-ray Spectrometer count rates resulting from astrophysical sources. ► A significant correlation between observed and predicted XRS features is found. ► Some astrophysical events coincide with magnetospheric electron detections. ► A correction to previously published electron fluxes is recommended as a result.