The New Spectral Image Processing System, known as NEWSIPS, is the
second (and final) generation standard production processing system
used for IUE data. The processing system
incorporated a number of improvements and enhancements in the reduction
algorithms, calibrations, documentation, and output formats of the IUE data.
The NEWSIPS-processed data, known as the IUE Final Archive,
generally provide improved signal-to-noise,
improved absolute calibration, and more homogeneous results for IUE
data than the IUESIPS-processed data.
Among the major enhancements are the following:
Improved construction of Intensity Transfer Functions (ITFs; linearization
Improved registration between ITFs and science data images using
Improved spectral extraction in low dispersion, using
optimal extraction techniques and corrections for aperture and temperature
Improved background correction using full-image modelling
techniques for high-dispersion spectra
Improved wavelength calibration, using new line library
Improved absolute calibration, based on white-dwarf models
Output files stored in FITS format for easier access
The history behind the development of the NEWSIPS system and creation of
the Final Archive, a discussion of the reduction techniques and new
calibrations, and an examination of the resulting processed data are discussed
in a paper by
Nichols and Linsky 1996.