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Getting Started

The International Ultraviolet Explorer (IUE) satellite was a unique space observatory in that it was operated like a ground-based observatory. Astronomers came to the Telescope Operations Center and directed their observations while observatory staff members commanded the instrument and read down the data in real time. It was launched on January 26, 1978, and operated for nearly 19 years until September 30, 1996. The instrumentation included two spectrographs, one from 2000 to 3300 Å and the other from 1200 to 2000 Å, in both high (R ~ 10,000) and low (R ~ 300) resolution modes.

The archive of over 107,000 spectral images includes about 9200 individual objects, many of which were observed repeatedly for variability studies. All types of astronomical objects, from planets to galaxies, were observed by IUE but a major portion of the archive is devoted to stellar observations. The search form may be used to select data from the IUE catalog by object name, coordinates, observing mode, date of observation, etc. The data files of interest may then be marked and retrieved.

MAST holdings contain the fully reduced and calibrated spectra in two versions. The first version consists of the original processed data using the IUE Spectral Image Processing Software (IUESIPS). The data files are stored in VICAR header format and can be read and analyzed with the IUE Data Analysis Center (IUEDAC) software package written in IDL. The data were later reprocessed using new calibrations and improved processing techniques (NEWSIPS), producing a second version known as the IUE Final Archive. The NEWSIPS data files are stored in FITS format and may be read with a variety of FITS readers, including iuetools in IRAF and programs in the IUEDAC software package. The Final Archive data are the preferred version for most applications, but both versions are available.