Frequently Asked Questions

Here are some questions frequently asked about the Multimission Archive at STScI. If your question isn't answered here or addressed in other pages, contact the Archive Hotseat.

Data

"What type of data are supported by MAST?"

The Multimission Archive at STScI supports:

• The Hubble Data Archive (HDA), which contains spectroscopic (1,100 - 11,000 Angstroms range; slitless spectroscopy up to 2.5 microns with NIC3) and imaging (1,150 - 25,000 Angstroms) data taken with Hubble Space Telescope. As of August 1998, the HDA contains over 5.2 Tbytes of science and engineering data, for a total of approximately 150,000 science exposures.
• The Far Ultraviolet Exporer (FUSE) covers the 905-1187 Å spectral region. This active mission contains high resolution spectra of hot and cool stars, AGNs, supernova remnants, planetary nebulae, solar system objects and the interstellar medium.
• The International Ultraviolet Explorer (IUE) Final Archive, which contains over 104,000 spectra of approximately 10,000 individual astronomical sources (covering the 1,200 - 3,350 Angstroms range).
• The Extreme Ultraviolet Explorer (EUVE) Archive, which at present contains spectroscopic observations (in the 70 - 760 Angstroms range) of about 300 sources, mostly Galactic.
• The Hopkins Ultraviolet Telescope (HUT) Archive, which contains 106 spectrophotometric observations of 77 targets were obtained in the far-UV (i.e., 912-1850 Å) at a resolution of ~3 Å. These were obtained during the first ASTRO mission. An additional 385 observations of 265 targets were obtained during the ASTRO-2 missions.
• The Ultraviolet Imaging Telescope (UIT) Archive, which contains 1,579 images of 259 targets (covering the 1,200 - 3,300 Å range) obtained by UIT as part of the ASTRO-1 and ASTRO-2 missions.
• The Wisconsin Ultraviolet Photopolarimeter Experiment (WUPPE) Archive, which contains 467 observations of 169 objects. WUPPE obtained simultaneous spectral and polarization measurements from 1400 to 3300 Å during the ASTRO-1 and ASTRO-2 missions.
• The Copernicus Archive, which includes far- (900 - 1,560 Angstroms) and near- (1,650 - 3,150 Angstroms) ultraviolet spectra of 551 objects, primarily bright stars.
• The Berkeley Extreme and Far-UV Spectrometer (BEFS), flew on the Orbiting and Retrievable Far and Extreme Ultraviolet Spectrograph (ORFEUS)-SPAS I and II space shuttle missions in 1993 and 1996, returning high-resolution (/3000) FUV spectra (900-1200 Å) of 75 astrophysical objects from the first flight and more than 100 from the second. EUV spectra (400-900 Å) were obtained for a subset of these targets.
• The The Interstellar Medium Absorption Profile Spectrograph (IMAPS) obtained high resolution (R=75,000 for IMAPS-1) objective-grating echelle spectra of hot stars, over the spectral region 950-1150 Å. The IMAPS archive currently contains roughly 600 spectral images of 10 hot stars from the first shuttle flight. Once the proprietary period ends for the second IMAPS mission, the archive will include an additional 3,900 spectral images of 29 stars
• The Tübingen Ultraviolet Echelle Spectrometer (TUES) flew on the Orbiting and Retrievable Far and Extreme Ultraviolet Spectrograph (ORFEUS)-SPAS II space shuttle mission in 1996, returning spectra in the 900 Å to 1400 Å wavelength range. The instrument was designed to achieve a spectral resolution of /=10000 when used with an entrance aperture of 10" diameter. During the 17.7 day flight, TUES returned 239 spectra of 62 targets.
• The Digitized Sky Survey (DSS). The Catalogs and Surveys Branch of the STScI has been digitizing the photographic Sky Survey plates from the Palomar and UK Schmidt telescopes in order to support HST operations and provide a service to the astronomical community. Archive users can easily retrieve image data for any part of the sky.
• The The Guide Star Catalog I (GSC I) is an all-sky optical catalog of positions and magnitudes of approximately 19 million stars and other objects in the 6th to 15th magnitude range. The GSC II is an all-sky catalog of approximately 2 billion stars and galaxies containing positions, magnitudes, colors and proper motions complete to a minimum of V =18.
• The Sloan Digital Sky Survey (SDSS) is using a dedicated 2.5 m telescope and a large format CCD camera to obtain images of over 10,000 square degrees of high Galactic latitude sky in five broad bands (u', g', r', i' and z', centered at 3540, 4770, 6230, 7630, and 9130 Å, respectively). The first data release, planned for June 2001, includes: imaging data containing a searchable catalog, images in several formats (FITS and JPEG), and spectra in both FITS format and GIF spectra with line identifications. This first public data release will contain over 500 square degrees of sky.
• The Faint Images of the Radio Sky at Twenty-centimeters (FIRST) Archive. The FIRST project is designed to produce a radio survey at 20 cm (1.4 GHz) of over 10,000 square degrees down to a flux of 1 mJy. MAST provides access to the radio images and the source catalog, which currently includes about 437,000 entries.
• The ROSAT, the RÖntgen SATellite, was an X-ray observatory developed through a cooperative program between Germany, the United States, and the United Kingdom. ROSAT data is maintained and archived at HEASARC. Except for the search and acknowledgments pages, all images and linked pages are provided by HEASARC.

Searching and Retrieving Data

"How do I search MAST?"

Every single archive can be searched using its search page. Links to the Web pages of the various archives included in MAST are available from the MAST main page. Moreover, for users wanting to search more than one archive at the same time, two interfaces are provided:

• From the MAST main page one can conduct a quick search by typing the name of a target to see if any of the MAST supported archives have observations of this target.
• The MAST Cross Correlation page provides a facility to allow the user to cross-correlate lists of positions with data in our archives. You can compile lists externally or use one of our online catalogs.

"How can I retrieve MAST data?"

All MAST data can be retrieved from the appropriate Web pages. Moreover, StarView can be also be used to retrieve HST, FIRST, and DSS data.

Documentation

"Are there manuals available for the MAST Archives?"

Yes. You can get them here:

• The HDA Manual
• IUE Reduction/Analysis Documentation
• IUE Instrumentation/Operations Documentation
• IUE Project Publications
• EUVE Project Publications
• Copernicus Reduction/Analysis Documentation
• Copernicus Instrumentation and Operations Documentation
• UIT Publications
• WUPPE Instrumentation and Operations Documentation
• HUT Instrumentation and Operations Documentation

"Is there a MAST Newsletter?"

Yes. It is sent out electronically to a distribution list. You can also read it on-line. If you would like to subscribe to the mailing list, please send e-mail to archive_news-request@stsci.edu and put the single word SUBSCRIBE in the BODY of the message.

More FAQ

More FAQ for the single archives are available on the following pages:

• HDA FAQ Page
• IUE FAQ Page
• Copernicus FAQ Page
• EUVE FAQ Page
• FUSE FAQ Page
• BEFS FAQ Page
• TUES FAQ Page
• GSC FAQ Page
• HUT FAQ Page
• UIT FAQ Page
• WUPPE FAQ Page
• DSS FAQ Page

User Support

Assistance is available for users of the various data included in MAST, although at different levels. Namely:

• Full support for HST data analysis.
• Full support for IUE data analysis (except for enhancement of post-pipeline data products).
• Moderate support for EUVE data analysis.
• Limited support for DSS, Copernicus, UIT, HUT, and WUPPE data analysis.

Questions about HST data analysis should be sent to help@stsci.edu. Questions about IUE, EUVE, Copernicus, and UIT data analysis should be sent to archive@stsci.edu.