Date, time, and solar activity for the VLT FORS 1 observations of the Patat (2008) spectroscopic data set. The solar activity is given by the solar radio flux measured at 10.7 cm in sfu. The FORS 1 spectra were taken with different instrument set-ups, which are indicated by different symbols and colours. The plot legend identifies the different set-ups by their covered wavelength ranges in μm. Open symbols indicate that the data were taken with the Moon above the horizon, whereas filled symbols refer to dark-time observations.