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5.5. Future Surveys

The All Sky Automated Survey (ASAS; is a project of the Warsaw University Astronomical Observatory ([Pojmanski 1997]). Its final goal is the photometric monitoring of ~ 107 stars brighter than 14mag all over the sky from various sites distributed over the world. The first results on variable stars found in ~ 100 square degrees have become available at the above URL.

While current Digitized Sky Surveys are all based on photographic material digitized off-line after observing, the future generation of optical Sky Surveys will be digital from the outset, like the ``Sloan Digital Sky Survey'' (SDSS;, [Margon (1998)]). The SDSS will generate deep (r'= 23.5mag) images in five colours (u', g', r', i', and z') of pi steradians in the Northern Galactic Cap (|b| > +30°). The SDSS will be performed in drift-scan mode over a period of five years. A dedicated 2.5m telescope at Apache Point Observatory (NM, USA;, equipped with a mosaic of 5x6 imaging CCD detectors of 20482 pixels will allow a uniquely large 3° field of view. Selected from the imaging survey, 106 galaxies (complete to r' ~ 18mag) and 105 quasars (to r' ~ 19mag) will be observed spectroscopically. The entire dataset produced during the course of the survey will be tens of terabytes in size. The SDSS Science Archive ( will eventually contain several 108 objects in five colours, with measured attributes, and associated spectral and calibration data. Observations are due to begin in 1998, and the data will be made available to the public after the completion of the survey.