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New Spectral Image Processing System (NEWSIPS)

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 calibration files)
  • Improved registration between ITFs and science data images using cross-correlation techniques
  • 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.

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