Motivation

Once interferometric data have been reduced and averaged using instrument-specific data reduction packages, they can, if they have been stored in the OIFITS format, be read by $\cal OYST\!ER\,$for calibration (if necessary), and further analysis employing models and images. In this way, the vast number of data analysis procedures written for $\cal OYST\!ER\,$can be used for any kind of interferometric data.