The DESI slit design: science and calibration solutions

The Dark EnergySurvey Instrument ( DESI) is a 5000-fibre optical multi object spectrographfor the 4m Mayall telecope at the Kitt Peak National Observatory. Ten identical three channel spectrographswill be equipped with 500-element fibre slits. Here we focus on the architecture of the science slitsand the interchangeableauxiliary slitsrequired for calibration.