There will be a number of exposures taken during day, twilight, and night time in order to ensure specified data quality. They are needed to correct for the fibre-to-fibre variations of the throughput, relative and absolute wavelength calibration, focal-ratio degradation when tilting fibre spines, and a number of other effects. These exposures will encompass:

  • Daytime calibrations (fibre flatfields and wavelength calibration, ccd zero (bias), dark, and flatfield)
  • Twilight calibrations (twilight flatfields)
  • Night-time calibrations (fibre flatfield and wavelength calibration attached to each science exposure)