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Paper: Cataloging of the Northern Sky from the POSS-II using a Next-Generation Software Technology
Volume: 61, Astronomical Data Analysis Software and Systems III
Page: 195
Authors: Djorgovski, S. G.; Weir, N.; Fayyad, U.
Abstract: Digitization of the Second Palomar Observatory Sky Survey (POSS-II) is now in progress at STScI. The resulting data set, the Palomar-STScI Digital Sky Survey (DPOSS), will consist of about 3 TB of pixel data. In order to extract useful information from this data set quickly, uniformly, and efficiently, we have developed a software system to catalog, calibrate, classify, maintain, and analyse the scans, called Sky Image Cataloging and Analysis Tool (SKICAT). It is a suite of programs designed to facilitate the maintenance and analysis of astronomical surveys comprised of multiple, overlapping images and/or catalogs. The system serves three principal functions: catalog construction (including object classification), catalog management, and catalog analysis. It provides a powerful, integrated environment for the manipulation and scientific investigation of catalogs from virtually any source. The system is a testbed for practical astronomical applications of AI technology, including machine learning, expert systems, etc., used for astronomical catalog generation and analysis. The system also provides tools to merge these catalogs into a large, complex database which may be easily queried, modified, and upgraded (e.g., as more or better calibration data are added). For example, we make a considerable use of the GID3* decision tree induction software. The resulting Palomar Northern Sky Catalog (PNSC) is expected to contain galaxies, and stars, in 3 colors ( ), down to the limiting magnitude , with the star-galaxy classification accurate to 90 -- 95 percent down to . The catalog will be continuously upgraded as more calibration data become available. It will be made available to the community via computer networks and/or suitable media, probably in installments, as soon as scientific validation and quality checks are completed. Analysis software (parts of SKICAT) will also be freely available. A vast variety of scientific projects will be possible with this data base, including the studies of large-scale structure, Galactic structure, automatic identifications of sources from other wavelengths (radio through x-ray), generation of objective catalogs of clusters and groups of galaxies, searches for quasars, variable or extreme-color objects, etc.
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