Standard Stars
The use of standard stars in order to allow for flux calibration and response correction, is foreseen only for IFU and ARGUS (integral field spectroscopy) observations. Unless otherwise indicated by the PI, the flux standard is chosen by the Night Astronomer from the Observatory list. In this case the science operation team at Paranal takes care of preparing the relevant Observing Blocks (OB) and execute the observations (usually during twilight). In the case of special needs,the user should provide their own OBs.