The image processing history includes the cumulative processing information generated by NEWSIPS. This history documents the processing system (software identification, version (if required), and hardware platform) and the individual application modules with the corresponding time stamps. Relevant variables used or computed by the various processing routines (e.g., median cross-correlation coefficient, dispersion constants, shifts used during the extraction, etc.) are also reported in the history. A complete processing history is included with every FITS file so that even the RILO/RIHI header contains this information. Chapter 13 explains the meaning and significance of those image processing history entries that bear directly on the quality of the derived data.
Each line of the history contains the keyword HISTORY in bytes 1 to 8, with processing information stored in bytes 9 to 74. Time stamps that designate the GMT times at which the individual application modules were executed are stored in bytes 65 to 72. Separate lines containing the processing date point out the start and end of the log. Examples of the processing history are outlined in the following subsections.