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Last Updated Jan 2001

Copyright 2001 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved.

Object Model

COMPASS is an object oriented database designed for the production of the second generation Guide Star Catalog (GSC-II). The database project is a collaborative effort between the Space Telescope Science Institute, USA and the Osservatorio Astronomico di Torino, Italy.

It will contain approximately two billion stars, galaxies, and other objects based on measurements of about 6000 sky survey plates. The data consists of:

  • Measurements and calibrations of individual astronomical objects up to 5 plates
  • Parameters of the individual plates
  • Externally produced catalogs with cross-indexing on which the physical calibrations are based on
    • Tycho
    • GSPC2
    • PPM
  • Full calibrations of the measured data
    • Positions
    • Brightnesses
    • Colors
    • Proper Motions

The object-oriented schema is built upon the commercial database, Objectivity, using a C++ binding for persistent objects. COMPASS storage hierarchy is based on 32768 sky areas, i.e. region databases, with links to a separate Plate database. The sky tessellation has been selected as part of a proposed community effort to construct a common partitioning of the celestial sphere. The intent of the common partitioning scheme is to ensure large-scale astronomical databases remain as interoperable as possible.