Source Searching

The two forms of ASTERIX data, binned and event datasets, are handled by PSS and EVPSS respectively. They have several features in common which are worth mentioning,

• They share many of the user interface prompts, such as those used for controlling the subset of the input dataset, names of output files, access to point spread functions and others.
• An EXPERT logical keyword is provided with both programs. Specifying this parameter false ensures the absolute minimum of user interaction -- usually supplying only the inputs is sufficient for default operation.
• Both have a diagnostic mode, which can be used either to produce evidence of a program's malfunction for the author's benefit, or as a useful supply of extra data for the expert user.
• They share output file format, both using source search results files, or SSDS. These data can be printed, displayed graphically or exported to other software packages.

EVPSS on the other hand is intended as a second pass parameterisation program. Current hardware limits the use of this program to relatively small areas of data -- typically circles around prospective sources.