A WWW Database of APS Poss Images

Abstract

We have used the Automated Plate Scanner (APS) at the University of Minnesota to digitize glass copies of the blue and red plates of the original Palomar Observatory Sky Survey (POSS I) with |b| > 20°. The APS Image Database is a database of all digitized images larger than the photographic noise threshold. It includes all of the matched images in the object catalog, as well as those unmatched images above the noise threshold. The matched image data of the catalog has the advantage of confirming the reality of the image. This is especially important for small images near the plate limit. But these are not all of the detected real images; very blue or very red faint objects may be excluded by this matching requirement. The image database allows information on them to be retrieved, and is therefore a valuable complement to the object catalog. The operation of the APS and the scanning procedures are described in detail in Pennington et al. (1993). We are now processing plate data into the image database. A set of query forms, a tutorial and documentation can be found at http://isis.spa.umn.edu/IDB/homepage.idb.html.