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326 about $300,000 per year beginning in 1983, it will be possible to establish and operate archives at most major U.S. observatories by the end of the decade. V I I . ASTRONOMICAL DATA BASES By astronomical data bases we mean collections of machine- readable tabular data such as star catalogs, tables of opacities, bibliographic data, and indices to observa- tional data. We draw a distinction between data bases and archives containing processed observations because the differences in data volumes and types imply differ- ences in storage volumes and access rates. A star catalog may contain entries for several hundred thousand stars and may have a much higher scientific information content than a digital image. However, the bit content of such a cata- log is equaled by that of only a few digital images. Users of a digital image generally require access to the whole image (or at least a substantial fraction of the image). Users of tabular data typically need data for only a small number of entries. Because the volume and access rates of tabular data are small, it is feasible with present-day technology, at modest expense, to (1) store these data bases in a few central locations, (2) generate cross-reference tables linking several catalogs, (3) make the data bases avail- able on a rapid access on-line medium, and (4) provide remote user access to data bases via inexpensive dial-up lines. Activities along these lines, especially for items (1) and (2), are already under way at a number of loca- tions including Strasbourg, France, and NASA/Goddard Space Flight Center, Greenbelt, Maryland. We believe that these collections of computer-readable astronomical data bases constitute an essential library resource for the astronomical community and that this resource is underutilized at present. We recommend that the data-base activities be continued and expanded and that implementation of remote access dial-in ports be implemented as soon as possible. As data archives are implemented (see the preceding section), copies of the indices of the archives should be maintained in the centralized tabular data bases. This will facilitate unified searches for all observations of a particular object or region of the sky. The construction of bibliographic data bases will be facilitated if journal editors require that each author submit with his or her
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