The first processing step in the photometric pipeline always consists of extracting source catalogs from the standard field data, and associating the results with a standard star catalog. These particular `association' catalogs are represented in the system by PhotSrcCatalog objects. To view the content of a PhotSrcCatalog object, simply invoke its inspect method:
which will result in an output to screen that looks like the one shown in Figure . The inspect plot shows the magnitudes of the individual standard stars as known to the standard star catalog on the x-axis, and their associated raw zeropoints on the y-axis.