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Published 1994 | metadata_only
Book Section - Chapter

Cataloging the Northern Sky Using a new Generation of Software Technology


We have developed a system, called SKICAT, for producing, managing and analyzing catalogs from the digitized POSS-II survey. The system classifies and matches catalogs from multiple, overlapping plate scans as well as CCD calibration sequences; and it can be used for the scientific analysis of the resulting catalogs. It incorporates a number of novel machine-learning and AI tools, including the star/galaxy classification using decision tree algorithms. This results in star/galaxy separation accurate to 90% or better down to B_j, ∼ 21^m, i.e. ∼ 1^m above the plate limit The final catalog is expected to contain at least 5 x 10^7 galaxies and > 2 x 10^9 stars. We present preliminary results on galaxy counts from a test region near the NGP. We find a mild excess over the no-evolution models, smaller than previously found by the APM group. A search for z > 4 quasars and the two-point correlation analysis of this data set are in progress.

Additional Information

© 1994 Springer Science+Business Media Dordrecht. This work: was supported at Caltech in part by the NASA AISRP contract NAS5-31348, Caltech President's fund, and the NSF PYI award AST-9157412, and at the JPL under a contract with the NASA. The POSS-II is partially funded by grants to Caltech from the Eastman Kodak Co., the National Geographic Society, the Samuel Oschin Foundation, the NSF grants AST 84-08225 and AST 87-19465, and the NASA grants NGL 05002140 and NAGW 1710. We acknowledge the efforts of the POSS-II team at Palomar, and the scanning team at STScl. We thank the conference organizers for a partial travel support, and an enjoyable meeting.

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August 22, 2023
August 22, 2023