The correct correlation of zero and first orders is crucial for grism analysis. Users should inspect the rotated image with fv or ds9 and verify the identification of the orders by overlaying the *SPCREG* region file, as shown in Fig. 9.3 (left); the *SPECLI* file also contains this informtaion. If users are interested in all source detections, the region file can also be overlayed and the full source list examined. Users should also examine the spectra plots automatically produced by omgchain, for both the source and background, making sure they are reasonable. For improved source detection, the parameter nsigma (in the GUI, ``Number of sigma for the detection algorithm'') can be changed.