Normalisation and compilation of the solar spectrum from observations of Vesta. The top panel shows the result of the division of the HERMES spectra by the Kurucz solar atlas for each individual exposure. Red dots indicate the supporting points for the cubic spline, depicted as a blue line. The regions of large deviations from the fit originate from contamination through telluric lines. The bottom panel depicts the resulting median spectrum obtained for the Vesta observations (in black) and the Kurucz (2005) spectrum (in red). The ratio between the spectra from Vesta and Kurucz are depicted as the blue line on the right hand y-axis. The regions used to determine the S/N in Strömgren b, and y as well as Johnson R and I, are indicated in the bottom panel as blue, green, red, and black dots, respectively.