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4.2. Other Ultraviolet Satellites

4.2.1. International Ultraviolet Explorer (IUE)

The International Ultraviolet Explorer (IUE) launched on January 26, 1978 had an extremely successful 18+ years of operations. Its detectors could obtain spectra from 1150Å to 3200Å. The telescope consisted of an f/15 45cm beryllium mirror. The spectrographs obtained data in a low- or high resolution mode (6 and 0.1 Å respectively). At high resolution it was capable of observing sources up to 12mag, while at low resolution the limiting magnitude was 17. Some characteristics of the spectrographs are shown in Table 4.

Table 4. Spectrographs

Short Wavelength Long Wavelength

Wavelength range (Å) 1150-1950 1900-3200
Resolving power 1.2 x 104 1.3 x 104
Low dispersion resolution (Å) 6 8

IUE data has been widely distributed, in particular the Uniform Low Dispersion Archive (ULDA).

4.2.2 IUE data

Spectra obtained with IUE consist of a 1-D file with 768 pixels. All reduced images contain a photometrically corrected image file and an extracted spectrum file. All short (SWP) and long (LWP) wavelength data has been reprocessed. The Space Telescope Science Institute is the repository of IUE's final archive. Retrievals can be made at European users might prefer to use the Spanish IUE node at

4.2.3 Extreme Ultraviolet Explorer

The Extreme Ultraviolet Explorer (EUVE) was launched on June 7, 1992. The satellite has 5 instruments: four photometric imaging systems and a three-channel EUV spectrometer capable of obtaining astronomical observations between 70 and 760Å.

During the first phase of the mission a four-band (at 100Å, 200Å, 400Å and 600Å) sky survey in the extreme ultraviolet and a long exposure "deep survey" were conducted. The catalogs and lists resulting from this survey are published in Malina et al. (1994) and Bowyer et al. (1996), and include 400 EUVE sources.

During the on-going second part of the mission a Guest Observer (GO) program consisting of pointed spectroscopic observations is carried out.

Each detector has an area of 72.44 cm2; other characteristics of the EUVE spectrometers used in the GO phase are shown in Table 5.

Table 5. EUVE spectrometer characteristics

short medium long

Bandpass (Å) 70-190 140-380 280-760
Resolution element (Å) .367-.636 .731-1.27 1.46-2.54
Filter material Lexan/boron Al/carbon aluminum
Transmission (Å) 1588/1172 1566/431 1553

4.2.4. EUVE Right Angle Program

This is a public program that makes data immediately available to the community. These images are obtained by the four imaging telescopes while the spectrometers are integrating for a Guest Observer program. RAP data has been available since the summer of 1996. The exposure time for these observations is such that allows the detection of sources ten times fainter than in the original survey.

4.2.5. EUVE Data

After the proprietary period expired (usually 1 year after the observations were made), the data are available through ADS and the EUVE public data archive. The data are distributed as a set of FITS files and tables. Its content is described in the EUVE GO Handbook available on-line at CEA (

The CEA now maintains a dedicated ADS node to provide sky survey data, EUVE calibration data, and pointed observations.

The on-line data available consist of:

A list of the pointed observations can be found at

A very handy Spectral Data Browser ( allows the user to select and retrieve public data directly from the WWW. The selection can be done by spectral type or by position.

Data is also periodically released on CD-ROM. The issued volumes include:

4.2.6. Astro Missions

The two Astro missions flew on board of the space shuttle and consisted of spectrographs, photometers and ultraviolet cameras. Astro-1 lasted 9 days in December 1990 and Astro-2 16 days in March 1995.

The instruments on board the Astro missions were:

BBXRT (Broad Band X-Ray Telescope) produced spectra between 0.3 and 10keV with a resolution of 90-200eV FWHM of around 80 sources during the Astro-1 mission

HUT (Hopkins Ultraviolet Telescope) produced spectra in the far UV (912Å-1850Å) with a 3Å resolution and in the extreme UV (415Å-912Å) with a resolution of 1.5Å for more than 300 sources

UIT (Ultraviolet Imaging Telescope) was a 38cm f/9 Ritchie-Chrétien telescope with two selectable cameras with a wavelength range between 1150Å and 3500Å. UIT included a set of Near and Far UV filters. The images were obtained on 70mm film that was scanned with different pixel sizes.

WUPPE (Wisconsin Ultraviolet Photopolarimeter Experiment) obtained simultaneous spectra and polarization measurement of 329 sources between 1400Å and 3200Å. The limiting magnitudes for these sources were between 0 and 8mag. WUPPE produced images in three sizes:

4.2.7. Astro Data

The data produced during the two missions is accessible through the Multimission Archive at STScI at The Web Interface for Searching Archival Research Data (WISARD) provides a way to retrieve archival data located in different archival sites. WISARD can be found at

4.2.8 Far Ultraviolet Spectroscopic Explorer (FUSE)

FUSE ( to be launched in 1999 will obtain high resolution between 905Å and 1195Å. It contains four slits:

The FUSE spectra will complement those obtained by HST as they are further in the UV.

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