DSS-II and GSC-II: STScI All-Sky Image and Catalog Databases
Abstract
A program of digitizing photographic sky survey plates (DSS-II), now quite close to completion, is approaching its final size, a 5 Tbyte collection of 1.1 Gbyte plate scans that cover the entire sky in 42 square degree fields. A set of image processing and object recognition tools applied to these data then results in a list of 4E9 (estimated) objects constituting the second Guide Star Catalog (GSC-II), which consists of positions, proper motions, magnitudes, and colors for each object. In order to preserve generality in the exploitation of these data, we maintain the connection between the images (plate scans) and the GSC-II catalog objects by associating the plate-calibration data (astrometry, photometry, classification) in FITS-like header structures pertinent to each plate. Internally, all the GSC-II data, ie, both the raw plate measures and the calibrated astronomical results, are stored in a database called COMPASS (Catalog of Objects and Measured Parameters from All-Sky Surveys). COMPASS, an object-oriented system built on the Objectivity (tm) DBMS, has an expected final size of 4 Tbytes, is structured for identifying systematic calibration effects so as to optimize the calibrations, and is organized on the sky with the hierarchical triangulated mesh developed by the SDSS Archive team. COMPASS is also used to support consistent object naming between plates, as well as cross-matching with other optical surveys and with data from other wavebands. A much smaller "export" catalogue, in ESO SkyCat format (about 100 Gbyte), will also be produced.
- Publication:
-
Astrophysics and Algorithms
- Pub Date:
- 1998
- Bibcode:
- 1998asal.confE...3L