Why does the script pcarsp seem to hang at the xpcaarf step?
The script pcarsp calls xpcaarf if you give it an attitude file (either the housekeeping file or the filter file) from which to derive the offset from the nominal source and pointing positions. There are two common occurrences of xpcaarf hanging, both simply having to do with giving it an unreasonably large offset. Firstly, though it may seem an obvious mistake to some, you cannot give xpcaarf an attitude file for a scan observation. If you wish to look at a spectrum collected over a scan, simply use “none” for the attitude file. This will tell the script not to try to account for the varying offset in computing the collimator response. Secondly, and more commonly, there is an extra step if you are using realtime data. Before processing, the data files do not have all keywords set correctly, most importantly the coordinates of the object. They have to be set by hand so that pcaarf will know how to compute the correct response. How to do this is detailed in the recipe Working with realt
