Synthetic spectrum of the solar simulation at full spectral resolution in the spectral range 2000–25 000 Å (grey, top panel) and 2000–12 000 Å (central and bottom panels). Several system response functions (Table 1), from which synthetic colours have been computed, are overplotted. Johnson-Cousins system response functions (U, B, V, Rc, Ic) are plotted in green and 2MASS in pink-violet (top left panel); SDSS (u, g, r, i, z) in yellow-red and Gaia (BP, RP, G) (top right panel); Strömgren (uvby) in red-blue and SkyMapper (u_s , v_s , g_s, r_s, i_s, z_s) (bottom left panel); and the 15 filters of the HST-WFC3 (bottom right panel). For clarity, SDSS and SkyMapper functions are normalised to 0.5.